Fill with pie weights. given that the pie dough bakes, its Fats will melt. The melting Fats causes the pie crust to shrink down the sides in the pie dish.
I’ve created this quiche 2 times and it’s turned out https://charlierncw447307.isblog.net/not-known-factual-statements-about-tortilla-quiche-bake-recipe-45764571