Traditional Basic Egg Quiche

Think of the egg-and-Gruyere classic
as a foundation for whatever embellishments
(ham, spinach, mushrooms) you add to it.

Ingredients:
1 9-inch refrigerated piecrust
2 tablespoons olive oil
2 medium onions, chopped
Kosher salt and black pepper
1 cup fresh flat-leaf parsley, chopped
4 large eggs
3/4 cup half-and-half
1/8 teaspoon ground nutmeg
8 ounces Gruyere, grated
4 cups mixed greens

Directions:
Heat oven to 375 degrees F.
Fit the crust into a 9-inch pie plate.
Place on a baking sheet.
Heat 1 tablespoon of the oil in a large skillet over medium-low heat.
Add the onions and 1/2 teaspoon each of salt and pepper and cook,
stirring occasionally, until soft, 5 to 7 minutes.
Stir in the parsley.
In a large bowl, whisk together the eggs,
half-and-half, nutmeg, and 1/4 teaspoon salt.
Stir in the onion mixture and the Gruyère.
Pour the egg mixture into the crust.
Bake until a knife inserted in the center
comes out clean, 35 to 40 minutes.
Let sit for 5 minutes.
Drizzle the greens with the remaining
tablespoon of oil and sprinkle
with 1/4 teaspoon each salt and pepper.
Serve with the quiche.