Preheat oven to 190°C (375°F) and blind bake the pastry crust for 10 minutes.
Sauté bacon in a skillet over medium heat until crisp, then drain excess fat.
In a mixing bowl, whisk together eggs, heavy cream, milk, nutmeg, salt, and pepper.
Distribute the cooked bacon and grated Gruyère cheese evenly across the bottom of the crust.
Pour the egg and cream custard over the fillings.
Bake for 30 to 35 minutes until the center is set and the surface is golden brown.
Allow the quiche to rest for 10 minutes at room temperature before slicing.