Italian pasta with a sauce of your choice

Why

A cooked potato is a cluster of cells full of swollen starch (see the Mashed potatoes card); when long kneading or blending ruptures the cells, the released starch forms a sticky mass with the water from the potatoes, more flour then gets added, and the dumpling turns out tough and gummy. Floury potatoes of cooking type C, or B, have more starch and less water and give a supple dough with less flour, whereas watery waxy potatoes of type A thin the dough; that is why the potatoes are boiled in their skins or baked and left to steam off and cool before use. Finished dough softens and gets sticky as it stands, and the more flour then goes in, the tougher the dumpling, so it is worked quickly and cooked at once. In the water it keeps its shape when the water only simmers and the surface sets quickly, whereas a hard boil and long cooking wear the surface away and the dumpling or gnocchi falls apart. Green patches, eyes and sprouts of potatoes contain bitter, toxic glycoalkaloids (solanine), so the German BfR advises removing them generously.

How to do it

1. Choose floury potatoes of type C, or B; boil them in their skins or bake them, peel and let them steam off and cool, even a day ahead in the fridge.
2. Cut out green patches and eyes generously; do not use green, shrivelled or heavily sprouted potatoes, or potatoes that taste bitter.
3. Grate the potatoes finely or put them through a ricer, do not blend them; add egg, salt and flour and bring the dough together quickly, just until smooth and holding its shape.
4. Add the flour gradually: first cook one small test dumpling or gnocchi and add more flour only if it falls apart.
5. Cook shaped dumplings and gnocchi at once, in small batches, in salted, gently simmering water; lift gnocchi out shortly after they float.
6. Take a cooked dumpling out at once, pierce it and slice it with thread or a sharp knife; move gnocchi straight into the sauce or melted butter so they do not stick together.

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Why

In the first minutes of boiling, starch is released from the surface of the pasta and it turns sticky; plenty of rapidly boiling water and a stir at that point stop it clumping, and the water doesn't cool down as much when the pasta goes in. Salt only gets into pasta while it cooks, which is why the water is salted generously, roughly 10 g per litre; that amount has a negligible effect on the boiling point, and oil in the water is pointless because it floats on top and doesn't prevent sticking. The cooking water is full of dissolved starch that thickens the sauce and helps its fat combine with water into a smooth emulsion that clings to the pasta. That is why pasta isn't rinsed after draining – you would wash off the starch the sauce holds on to and cool the pasta down; the only exception is pasta for a cold salad.

How to do it

1. Allow roughly a litre of water per 100 g of pasta and add about 10 g of salt per litre once it boils.
2. Drop the pasta into rapidly boiling water and stir now and then for the first two minutes.
3. Don't add oil to the water; it won't stop sticking.
4. Cook a minute or two less than the packet says and keep tasting.
5. Before draining, scoop out a mugful of the cooking water.
6. Don't rinse the pasta; transfer it straight into the sauce and finish cooking it there with a little of the cooking water.

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Why

In wheat dough the gluten network holds both gas and shape (see the Kneading and gluten card); rice, maize, buckwheat or millet flour and starches form no gluten, so without a substitute the dough does not rise, bread crumbles and a dumpling falls apart in the water. Binders imitate the network: psyllium (husk fibre from Plantago seeds), xanthan gum or egg form a thick gel with water; psyllium binds far more water than xanthan, so gluten-free dough needs more liquid, tends to be soft or even sticky, and its flours need time to absorb the water, otherwise the bread is gritty. Gluten-free bread is mostly starch, which firms up again after baking, so by the next day it is hard and it tastes best fresh or toasted. In coeliac disease even traces of gluten do harm: under EU Regulation 828/2014 a food labelled “gluten-free” may contain at most 20 mg of gluten per kg and any oats in it must be grown and processed separately, and a crumb from a chopping board, a shared toaster or oil used for breaded food can carry a similarly small amount into a dish.

How to do it

1. Do not replace wheat flour 1:1 with a single gluten-free flour; use a blend of flour and starch with a binder, or a recipe written for gluten-free dough.
2. Stir psyllium into the water first and let it gel; work the dough until soft or even sticky and shape it with wet hands, as stiff dough cracks and crumbles after baking.
3. Let the dough rest for a while before baking or boiling so the flours absorb the water; long kneading does not help, as no gluten forms in it.
4. Cook gluten-free pasta in plenty of water, start tasting earlier than the packet says and serve it at once; it sheds more starch, softens quickly when overcooked and sticks together as it stands.
5. For a coeliac, cook the gluten-free dish first, in clean pans and water; keep a separate toaster or toaster bags, uncontaminated butter and spreads, and clean frying oil.
6. Buy flours, flakes, starches and mixes labelled “gluten-free”; wheat, rye, barley and spelt contain gluten, ordinary oats are often contaminated, and a few coeliacs react even to gluten-free oats.

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Why

When you reduce a sauce, simmering it uncovered, water evaporates while flavour compounds, sugars, gelatin from meat and bones and salt stay in the pan, so they become concentrated and the sauce thickens. If you salt it at the start and then reduce it by half, it will be roughly twice as salty – which is why seasoning is adjusted at the end. The brown bits stuck to the bottom of the pan or roasting tin after searing or roasting (the fond) are among the tastiest parts of a sauce: poured over with stock, wine or water and scraped up, they dissolve into the sauce – this is called deglazing. A gentle simmer is enough; at a hard boil the sauce easily scorches at the edges and on the bottom, and if it contains a lot of sugar or gelatin it reduces into a sticky mass.

How to do it

1. Cook uncovered in a wider pan so the water evaporates faster.
2. Salt only at the end, once the sauce has the thickness you want.
3. Pour hot stock, wine or water over the fond and scrape it off the bottom with a wooden spoon; leave out black, burnt bits, they would make the sauce bitter.
4. Keep only a gentle simmer and stir now and then, especially at the bottom and the edges.
5. Test the thickness on a spoon: the sauce should coat it thinly; bear in mind it will thicken further as it cools.

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Why

Tomato paste is concentrated tomato flesh with plenty of sugars and acids; briefly fried in fat, some of the sugars brown and the raw, sharply sour taste turns full and rounded, but it must be stirred, because it scorches easily on a dry pan base. Long simmering, fat, cream or a little sugar soften a sharp sauce; sugar doesn't neutralise the acid, though, it only balances it on the palate. Baking soda really does neutralise acid, but in tests it made the sauce taste flat, and larger amounts foam and taste soapy, so a pinch at most. Acid firms up the cell walls of vegetables and pulses, so beans, chickpeas and potatoes soften more slowly in tomato sauce. Acidic food doesn't belong in uncoated aluminium: the German BfR advises against cooking or storing acidic and salty food, such as tomato purée, in uncoated aluminium pots, because aluminium migrates into it; with cast iron, manufacturers say long cooking of acidic food strips the protective seasoning.

How to do it

1. Stir the paste into hot fat and fry it for a few minutes, stirring constantly, until it darkens and smells sweet; then add liquid at once.
2. Simmer a sour sauce for longer and round it off with fat or cream; add sugar little by little and taste.
3. Use baking soda only as an exception, a pinch per pot at most, and let it fizz out before tasting.
4. Cook beans, chickpeas and potatoes until tender first, or allow longer cooking in the sauce – see the Cooking pulses card.
5. Cook and store tomato sauces in stainless steel, enamel or glass, not in uncoated aluminium or new, lightly seasoned cast iron.

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Why

The fat in bacon and in pork back fat is held in the cells of fatty tissue bound together by connective tissue; heat liquefies the fat so it gradually runs out, the water evaporates, and the lean parts shrink and turn crisp. This takes time, which is why bacon goes into a cold pan, even with a little water, and is heated over medium heat: the water keeps the temperature low at first, the fat renders before the surface scorches, and the bacon crisps evenly. In a fiercely hot pan the surface burns, the fat blackens and smokes, and the fatty parts stay rubbery. Pork fat for cracklings is rendered over gentle heat with frequent stirring until the cracklings are light brown and crush easily; overcooked cracklings give dark lard with a burnt taste. Bacon cured with nitrite also forms nitrosamines when fried over fierce heat, and EFSA regards dietary exposure to nitrosamines as a health concern, so this is one more reason to fry bacon until crisp, not black.

How to do it

1. Cut the bacon into slices, strips or cubes of even thickness, spread it in a cold pan in a single layer and, if you like, add about 4 tablespoons of water.
2. Heat over medium heat and turn it now and then; the water evaporates and the bacon then keeps frying in its own fat.
3. Take the bacon out as soon as it is golden brown; it crisps further on paper towel, and if it is dark while still in the pan, it is overcooked.
4. Cut pork fat for cracklings into even cubes and render it in a heavy pot over gentle heat, stirring often, until the cracklings turn golden.
5. Carefully strain the hot lard through a sieve into dry jars and keep it covered in the fridge once cool; never add water to hot fat, it boils up violently and spatters.
6. Use the fat rendered from bacon to soften onions or vegetables; let the rest set and put it in the bin, not down the drain.

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Why

The heat of chillies comes from capsaicin and related compounds, which stimulate the receptors for pain and heat; most of it sits in the white membranes inside the pod that hold the seeds, while the seeds themselves make none and are only coated with it. Capsaicin barely dissolves in water but dissolves well in fat and alcohol, so chilli fried in oil spreads its heat through the whole dish and water does not soothe a burning mouth – cold milk or yoghurt works better. In a dry, very hot pan or in very hot fat, capsaicin is released into the air and stings the eyes and throat, and dried chilli also scorches easily and turns bitter. Dried chilli has lost its water, so the same weight is usually hotter than fresh, and its flavour is more roasted and less fresh.

How to do it

1. Wear gloves when cutting hot chillies and keep your hands away from your eyes; take contact lenses out beforehand.
2. For milder heat, cut out the white membranes together with the seeds; scraping out only the seeds lowers the heat very little.
3. Fry chillies and chilli flakes in fat only briefly over gentle heat and ventilate the kitchen; once they darken, they turn bitter.
4. Add chilli a little at a time and taste, as the fat in a sauce carries the heat through the whole pot.
5. Wipe the burn off your skin first with a little oil and a paper towel, then wash your hands thoroughly with soap and water.

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Why

Many of the aroma compounds in spices, the so-called essential oils, dissolve far better in fat than in water; when spices are fried briefly in hot oil or ghee, their aroma is released into the fat, which then carries it through the whole dish. Whole seeds such as cumin, mustard or coriander can take several tens of seconds in hot fat, while ground spices, with their much larger surface, scorch far sooner, often within half a minute; garlic and ginger go in after the seeds and are fried only until golden. A tadka (also chaunk or baghaar) is made either at the start of cooking, with onion or tomatoes following straight after the spices, or at the very end, when the hot spiced fat is poured into the finished dish, dal for example. Well-bloomed spices smell nutty and warm, underdone ones taste raw and dusty, burnt ones bitter.

How to do it

1. Measure out all the spices beforehand; a tadka takes only moments and won't wait while you hunt for a jar.
2. Heat the fat to about 160–170 °C; a test seed should sizzle straight away.
3. Add the whole seeds first and fry them for about 30 seconds, until fragrant and a shade darker; mustard seeds until they pop.
4. Add ground spices last, or together with something moist such as onion or tomatoes that cools the fat down.
5. Fry garlic and ginger only until golden; browned garlic turns bitter.
6. Pour the finished tadka, fat and all, into the dish at once; in the hot pan it would keep darkening.

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Why

When the blades start, hot liquid in a blender jar is churned violently and releases a lot of steam; if it has nowhere to go, pressure builds up in the jar, which can lift the lid and spray soup over hands and face. Manufacturers' instructions differ, though: some advise filling the jar no more than half full, preferably a third, removing the centre cap and covering the opening with a towel, others want the vented cap left in place, and some don't allow hot liquids at all or only up to a set temperature; they agree on starting at the lowest speed. Sealed smoothie cups without a vent should not be used for hot ingredients at all. An immersion blender largely avoids this risk, because the soup doesn't have to be transferred and the pot stays open; even so, take the pot off the heat. With potatoes, watch the texture too: long or fast blending releases starch from the cells and the soup turns gluey, as the Mashed potatoes card explains in more detail.

How to do it

1. Let the soup stand for a few minutes after cooking and don't blend it boiling; if the blender manual gives a maximum filling temperature, keep to it.
2. Fill a blender jar no more than half full, preferably a third; blend larger amounts in batches.
3. Fit the lid as the manual says: remove the centre cap and cover the opening with a towel only where the manufacturer advises it; otherwise keep the vented cap in place. Always hold the lid down.
4. Start on the lowest speed and only increase it gradually.
5. Where possible, use an immersion blender in a pot taken off the heat; submerge the blade before switching on and lift it out only after switching off.
6. Blend soups with potatoes briefly, just until smooth, or mash the potatoes instead.

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Why

Salt suppresses bitterness much more than sweetness, so it not only seasons a dish but rounds it out, and bitter vegetables taste milder once salted. When to salt depends on the method: pasta water right away (see the Cooking pasta card), meat either well ahead or just before searing (see the Salting meat ahead card), and anything that will be reduced for a long time only at the end, because the evaporating water leaves the salt in the pot (see the Reducing a sauce card). Acidity from lemon, vinegar or wine is the second lever of seasoning: a dish that tastes flat although it has enough salt is often missing exactly that, and acid also balances strong sweetness or richness. A raw potato will not rescue an over-salted dish: it soaks up a little salty liquid, but what is left in the pot is just as salty, so only diluting with an unsalted base helps.

How to do it

1. Salt gradually and taste; salt added at the start of a long simmer becomes concentrated as the liquid reduces.
2. Adjust the salt in soups, sauces and braises only at the end, once they have the consistency you want.
3. When a dish tastes flat although it is salty enough, add a drop of lemon juice or vinegar first, not more salt.
4. Taste bitter vegetables only once salted, before you start correcting their bitterness with sugar or cream.

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