Mix flour, salt, and butter for the crust; add ice water. Chill for 30 minutes.
Roll out dough; fit into a 9-inch pie dish. Chill for 15 minutes.
Preheat oven to 375°F; blind bake crust for 20 minutes.
Cook bacon until crispy; sauté onion in bacon fat.
Whisk eggs, cream, milk, salt, pepper, and nutmeg; add bacon, onion, and cheese.
Taste and adjust the filling with salt or nutmeg.
Pour into crust; bake for 30–35 minutes until set.
Cool for 10–15 minutes; serve on a white ceramic platter.