Shortbread

Yes. Store cooled shortbread in an airtight container at room temperature for up to 1 week, or freeze in a freezer-safe container for up to 1 month; thaw at room temperature for 15 minutes before serving.

Cold butter will not cream properly and the dough will be lumpy; always soften butter to room temperature first so it blends smoothly with the sugar.

You have either overmixed the dough (which overdevelops gluten and incorporates too much air, causing spread and greasiness) or used too-soft butter; mix gently until just combined and use butter softened to 65–70°F.

Yes. After pressing into the pan, you can use a knife to score it into shapes (wedges, squares, rectangles, diamonds) before baking, or let it cool and cut cleanly with a sharp knife; pressing fork lines or using a decorative fork helps mark the portions before baking.

Shortbread is 1 part sugar to 2 parts butter to 4 parts flour and contains no eggs or leavening, yielding a tender, melting texture; sugar cookies use less butter, often include eggs or leavening, and are rolled and cut into shapes. They are distinct cookies.

Yes, but subtly. Add 1 tablespoon of lemon zest, 1/2 teaspoon of vanilla extract, or 1/4 teaspoon of almond extract with the flour; or press a few dark chocolate chips or candied peel pieces into the surface before baking. Keep additions minimal so the butter flavor remains dominant.