Heat your oven to 425°F. On a lightly floured surface, roll out the pie scraps (or refrigerated pie crust) to ⅛-inch thick. Cut out twelve 4-inch rounds.

Place each round in a standard Mason jar lid (2 ¾-inch diameter), and slightly crimp the edges.

Line each round with parchment paper and fill with dried beans or pie weights. Bake at 425°F until beginning to brown, about 12 minutes. Let cool while preparing the filling.

Heat the oven to 375°F.

Sauté the ham and onions in butter over medium heat until the onions are translucent and the ham is browned. Allow to cool slightly.

Divide the ham and onion mixture among the 12 quiche crusts, about 1 tablespoon per crust. Top each with a heaping teaspoon of shredded mozzarella cheese.

In a large measuring cup, whisk together the eggs, sour cream, nutmeg, salt and pepper. Divide the egg quiche filling mixture evenly among each crust.

Bake at 375°F until just set, about 15 minutes. Cool before serving.