Preheat oven to 400°F. Arrange pie crust in pie pan and crimp edges as desired. Prick bottom of the crust with a fork. Chill crust in the freezer for 30 minutes.
1 pie crust
Line the inside of the crust with foil or parchment, then fill with pie weights or dry beans. Bake crust for 20 minutes, then remove foil and weights and bake another 5-8 minutes. Let cool and reduce oven to 350°F.
In a bowl, whisk together eggs, cream, milk, garlic powder, salt, and pepper until blended. Stir in the diced ham.
3 eggs, 3/4 cup heavy cream, 3/4 cup milk, 1/2 teaspoon garlic powder, 1/2 teaspoon fine sea salt, 1/4 teaspoon ground black pepper, 1 cup diced cooked ham
Place pie pan on a rimmed baking sheet to catch spills. Use a pastry brush or back of a spoon to spread the dijon mustard onto the bottom in an even layer.
1 tablespoon dijon mustard
Pour in half the egg mixture, using a spoon to make sure the ham is distributed evenly. Top with half of the cheeses. Carefully pour in the remaining egg mixture, top with the remaining cheese, then the chives.
1 cup shredded cheddar cheese, 1/2 cup shredded Swiss cheese, 2 tablespoons chopped fresh chives
Carefully transfer quiche, on the baking sheet, to the oven and bake at 350°F for 40-45 minutes, until lightly browned and center is set and just barely jiggly.
Let cool on a wire rack at least 15 minutes before serving.
Notes
If your ham is salty, reduce the added salt to 1/4 teaspoon.
Store leftovers, well wrapped, in the refrigerator for up to 4 days.