for quiches, onion tarts, etc. (this is called pâte brisée)
mix: 2.5 cup flour, 1 tsp salt
slice into the bowl: 1 cup cold butter
using fingers, break the butter into smaller and smaller pieces. as it mixes with the dry ingredients, it will eventually form a mealy texture. remember to break, not squeeze. this is called "cutting in".
once you have an even meal, dribble water into the bowl 1 tbsp at a time, now squeezing the dough together until it forms a ball. as soon as it's all able to stick together, the dough is done. do not knead or work the dough.
use plenty of flour to prevent this delicate dough from sticking. roll to a thickness of 1/8-1/4 inch. if you are using a tart pan with a removable bottom, roll the dough out directly onto the tart pan so you don't have to move it. if you do have to move the dough, such as into a pie pan, it may break, but you can repair it by just pushing on it once it's in place.
some vegetables can be put in raw: asparagus, corn, tomatoes, red onions, spinach. others should be cooked: white onions, leeks, mushrooms, kale, bacon
roll out 1/2 batch of dough and fold into a tart pan.
put the vegetables and cheese if you want into the bottom of the pan
then pour in the following, which you have mixed in a bowl: 4 eggs,1 cup cream (yogurt is even better), 1 tsp salt, pinch nutmeg, pinch black pepper)
bake for about 30 minutes at 350 degrees until a toothpick inserted comes out cleanly.