Prepare the crust:
In a mixing bowl, combine the flour and salt. Cut in the chilled butter using a pastry cutter or fork until the mixture resembles coarse crumbs.
Gradually add cold water, 1 tbsp at a time, mixing until the dough comes together. Form into a disk, wrap in plastic, and refrigerate for 30 minutes.
Roll out the dough on a floured surface and fit it into a pie dish. Trim the edges and chill for 15 minutes.
Pre-bake the crust:
Preheat your oven to 375°F (190°C). Line the crust with parchment paper and fill with pie weights or dried beans.
Bake for 15 minutes, remove the weights, and bake for another 5 minutes. Set aside to cool.
Make the filling:
In a mixing bowl, whisk together the eggs, heavy cream, milk, salt, pepper, and nutmeg (if using).
Assemble the quiche:
Sprinkle half of the cheese over the bottom of the crust. Add the bacon, ham, or vegetables, then pour the egg mixture over the top. Sprinkle the remaining cheese on top.
Bake the quiche:
Reduce the oven temperature to 350°F (175°C). Bake for 35–40 minutes, or until the filling is set and slightly golden. Allow to cool for 5–10 minutes before slicing.