Parbake pie crust. Press the dough around the edges of a 9-inch tart pan or pie dish. Place on a baking sheet. Pierce the bottom of the pie crust with a fork. Bake for 5 minutes and then remove from oven. Set aside.
Saute. In a small frying pan, melt 1 Tbsp butter over medium heat. Add 1/2 cup onions and sauté 2 minutes. Stir in 1 cup ham and 1/4 cup bacon pieces and cook an additional 3 minutes, or until the onions have caramelized. Remove from heat and let cool slightly.
Make egg filling. In a large bowl, whisk together 5 eggs and 2/3 cup half-and-half. Stir in 1 cup cheddar, 1/2 cup mozzarella, 1/2 teaspoon parsley flakes, 1/4 teaspoon pepper, 1/2 - 1 cup spinach, and the ham mixture. Pour into the tart pan.
Bake. Bake for 25 to 35 minutes, or until the top is golden brown and a toothpick inserted in the center comes out clean. Remove from oven and let cool slightly. Enjoy while warm!
Notes
Milk substitution: I prefer half-and-half because it makes quiche extra creamy and delicious but in a pinch milk can be used.Store: Cool completely, then wrap the pan tightly with aluminum foil or plastic wrap. Place in fridge for up to three days.Freeze: Freeze leftover quiche for up to two months. To reheat, cover with foil and bake at 400°F until it is warm throughout.