Shrinkage

In pastry, shrinkage usually comes from gluten that was stretched while rolling or fitting the dough into the pan; the strands snap back in the oven. Resting the dough in the refrigerator before rolling and again after lining the pan lets the gluten relax, and easing the dough in without stretching helps too.

For blind baking, docking the base and filling the shell with pie weights keeps the sides upright. Cakes also shrink slightly from the pan as they cool, which is normal unless excessive.