Christmas biscuits from butter dough

Why

Butter softens even at room temperature and above about 30 °C is almost entirely liquid, and while it is firm in the dough the cut shape holds; if it melts before the proteins and starch set in the oven, the biscuit spreads. Spreading is therefore encouraged by warm or melted butter, dough warmed by your hands and a hot baking sheet, but also by more sugar and by bicarbonate of soda; icing sugar and starch give tender, short biscuits (the proportions of Linz dough are covered in the Shortcrust pastry and cold butter card). Small, thin biscuits bake quickly and their edges brown first; honey and fructose brown more readily than beet sugar, so gingerbread darkens faster. Baking until dark increases acrylamide in biscuits, which is why EU regulation requires producers to bake to a lighter colour and to consider reducing or replacing ammonium bicarbonate, a raising agent that strongly promotes acrylamide formation. After baking, biscuits exchange moisture with the air and with their neighbours: honey gingerbread and Linz biscuits sandwiched with jam soften within days in a closed tin, and crisp biscuits stored with them lose their crunch.

How to do it

• Wrap the dough once it comes together and chill it for at least 30 minutes; roll and cut it cold and press the scraps together quickly, without long kneading.
• Place cut biscuits on a cool baking sheet lined with baking paper; let the sheet cool between batches or alternate two.
• In a warm kitchen, put the sheet of cut biscuits in the fridge for 10 minutes and then straight into the oven.
• Bake pieces of the same size and thickness only until light golden, usually at 160–180 °C; watch biscuits with honey and thin edges, they darken fastest.
• Let biscuits firm up on the sheet for a few minutes, then cool them on a rack; use ammonium bicarbonate only in thin, dry biscuits, it does not escape from thick ones.
• Store crisp and soft biscuits separately in closed tins; leave gingerbread and sandwiched Linz biscuits to mellow for 1–3 days before serving so they soften.

If it goes wrong

Straighten biscuits that have spread as soon as they come out, while still soft, with a larger cutter or a knife. Return dough that sticks and smears to the fridge for 20–30 minutes and roll it between sheets of baking paper. Carefully grate off slightly darkened edges with a fine grater; burnt biscuits are bitter, throw them away. Hardened gingerbread softens in a closed tin with a slice of apple within 1–2 days; then remove the apple. Refresh softened crisp biscuits for 3–5 minutes at 150 °C.