Mix brownie mix, melted butter, sugar, and salt in a bowl until coarse crumbs form.

Press mixture evenly into a 9-inch pie pan, up the sides and across the bottom, using the back of a spoon or a measuring cup.

Chill crust in the fridge 30 minutes to firm up; if you need it faster, freeze 10–15 minutes.

Fill with no-bake fillings like chocolate mousse, cheesecake filling, or pudding. Keep refrigerated until serving.