In many tarts and pies, the fillings are delicate and can't bake as long as the crust, or some cream fillings shouldn't be near the oven at all. So the crust is baked before hand to ensure an even and complete bake. No one likes raw pie dough, and no one wants baked chocolate pudding. Sounds pretty simple, right?
Due to the high butter/shortening content of pie dough, there's also a good bit of moisture. This can cause the crust to bubble and inflate as it bakes, without the weight of the filling pressing it down. So to counter this rise, the dough is covered with a layer of oven-safe weights. These weights can be like the porcelain nuggets I have, or even dried beans or rice. As an added bonus, they will also absorb the heat and bake the top of the crust as well.
Because the dough is covered with parchment paper or cling-wrap, and then covered with weights, you can't really see what's happening. Voila! Now you're blind. Really I'm not sure how this is different from normal baking, but whatever.
1. Fit your dough.
Roll out your pie dough and fit it into whatever tin you are using. Trim the edges and prick with a fork. Cover and put in the fridge for 30 minutes. This is a good time to preheat your oven to the desire temperature (varies).
When the dough is firm and chilled, cover with parchment paper or oven-safe cling wrap.
3. Fill with beans.
Pour in about 1 1/2 cups of beans or oven safe pie weights.
4. Bake it blind.
This varies per recipe. Rest the tart tin in the middle of the oven, and trim the parchment paper if it's unwieldy.
5. Bake it un-blind.
When it's ready, remove from the oven and VERY CAREFULLY lift the weights from it. Because they just came from the oven, they will be hot! Please don't for get this. Have something ready to collect them in once you remove them. Then the recipe might ask to bake the crust a little longer san filling or weights, or to pour in the filling and bake normally. Either way, just pop it into the oven and bake to a golden brown.