Preheat oven to 325 degrees F. Mix butter, flour, and powdered sugar in a medium bowl until crumbly.
In an 8-inch or 9-inch pie plate, pat the crumb mixture evenly, being sure to come up the sides to the edge. Crimp the dough with a fork or fingers.
For a pre-baked crust, such as an icebox fruit pie, cream pie, or chiffon pie, bake for 25 minutes.
