How do I stop my pastry shrinking?
This has happened to me on occasion when I got lazy and tried to skip steps. My pastry walls were melting and sliding down the pan before they were able to set.

There are several best-practices that will help solve this:


Keep your dough chilled. If the dough is warm or if it is built into a warm pan it will melt in the oven before it has a chance to set.
Make a better lip (if there is one). A more substantial edge around the pastry will give some physical support to prevent falling.
Use foil and pie weights to reinforce the structure during the beginning of baking.