Prickly Subject: The Importance of Docking Your Pastry

The instruction to “prick the base all over with a fork” before filling your crostata is a small but critical step known as “docking.” This simple action is the key to preventing a domed, puffy, and unevenly cooked base, ensuring your tart has a flat, crisp foundation.
When the pastry base heats up in the oven, the water content in the butter turns to steam. If this steam is trapped underneath the dough, it will expand and cause the pastry to puff up in large, uneven bubbles. This can lead to a soggy, undercooked center and an unstable base for your jam filling.
By pricking the dough with a fork, you are creating dozens of small vents. These holes allow the steam to escape from under the pastry as it bakes. This prevents the dough from rising and ensures that the base remains flat against the bottom of the tin, allowing it to cook evenly and become perfectly crisp.
You don’t need to go overboard—a gentle pricking every inch or so is sufficient. You want to pierce the dough but not necessarily go all the way through to the tin. The goal is simply to give the steam an exit route.
This technique is essential for any single-crust tart or pie, especially when the filling is wet like jam. It’s a simple, two-second step that solves a major potential problem, guaranteeing a perfectly flat and crisp foundation for your delicious blackberry and bay filling.