This quiche can be filled with any type of fillings your heart desires and is great warm or at room temperature.
2 tablespoons olive oil
1 small yellow onion, diced
2 cups baby spinach
2 tablespoons butter, softened, plus more for greasing pan
1 (20-ounce) package of hash browns, I use Simply Potatoes from the refrigerated section. Alternatively, use frozen hash browns and thaw them.
12 large eggs
2 teaspoons coarse kosher salt, divided
1 teaspoon freshly ground black pepper, divided
1 teaspoon aleppo pepper flakes, or you can substitute with red pepper flakes
2 tablespoons sour cream
1/4 cup shredded Parmesan cheese
1 tablespoon chopped parsley
Heat the olive oil over medium high heat. When heated add the onion and cook for 5 minutes until they are translucent. Add the baby spinach a cup at a time turning with tongs to wilt the leaves. When all of the spinach has been added and the leaves are wilted down turn off the heat and set the mixture aside to cool.
Preheat the oven to 375°F. Lightly grease a 9 x 2 1/2-inch spring form pan with butter. Line the bottom and sides of the pan with strips of parchment paper and grease the paper with butter as well.
Place the hash browns into a kitchen towel and squeeze tightly to remove any excess water. Transfer to a large mixing bowl then use your hands to mix the hash browns with the 2 tablespoons of softened butter, 1 egg, aleppo pepper flakes, 1 teaspoon salt, and 1/2 teaspoon pepper. When thoroughly mixed place the potatoes into the spring form pan and pat gently into the bottom of the pan and up the sides. *A measuring cup, slightly dampened, really aids in this process. When the hash browns start to stick to the measuring cup dampen it again. Place the pan on a rimmed baking sheet and bake until the crust has set. Anywhere from 15-20 minutes.
In a blender combine the sour cream, 1 teaspoon coarse salt, 1/2 teaspoon pepper, Parmesan cheese, and the remaining 11 eggs and blend until the mixture until smooth. Add the cooked spinach and onion mixture to the blender and pulse a few times to incorporate then pour the egg mixture into the prepared hash brown crust. Bake until set, 40-50 minutes. Remove quiche from pan and allow to cool slightly before peeling away the parchment paper. Sprinkle with chopped parsley before serving. This quiche is great warm and at room temperature.
If using frozen hash browns: You will have a lot more liquid released from the potatoes when you drain them in the kitchen towel.
You can make the hash brown crust a day ahead of time to make prep easier.