Mushroom, Spinach   Mozzarella Mini Crustless Quiches  Makes 12 muffin-size quiches  Cooking spray  2 Tablespoons olive oil  1 small onion, diced  5 ounces fresh baby spinach  6 ounces crimini or button mushrooms, sliced  5 eggs  1 cup grated mozzarella cheese  1/2 cup 2 % milk  1/2 teaspoon Kosher salt  1/4 teaspoon freshly ground black pepper  Preheat the oven to 350 degrees F.  Generously spray a standard-sized muffin tin with cooking spray,   saute olive oil   onion about 5-8 minutes.
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