Preheat your oven to 375°F (190°C).
Place the pie crust in a pie dish and set aside.
Cook the bacon in a skillet over medium heat until crispy. Remove and drain on paper towels.
In the same skillet, cook the onions until soft.
In a mixing bowl, whisk together the eggs, heavy cream, milk, salt, pepper, and nutmeg.
Spread the cooked bacon, onions, and shredded cheese evenly over the pie crust.
Pour the egg mixture over the bacon, onions, and cheese.
Bake in the preheated oven for 45 minutes, or until the quiche is set and golden brown on top.
Let the quiche cool for a few minutes before slicing and serving.