2 tablespoons olive oil 2 cups sliced onions 8 ounces sliced mushrooms 1 1/2 cups frozen chopped spinach, thawed and squeezed dry 8 eggs 1 cup milk 2 teaspoons mushroom or chicken concentrate 1 cup grated Italian fontina cheese Salt and freshly ground black pepper to taste
Preheat oven to 375°.
Heat oil in tall nonstick skillet over medium heat. Stir in onion and mushrooms. Saute 12–14 minutes or until golden brown and dry. Distribute spinach in even layer over mushrooms.
Whisk eggs, milk, mushroom concentrate and cheese in a bowl. Season mixture with salt and pepper. Pour egg mixture over onion mixture, and stir gently. Cook 3–4 minutes, until a firm bottom layer forms.
Place pan in oven, and cook 18–20 minutes or until mixture firms. Remove from oven and let stand 5 minutes. Turn frittata bottom side up onto cutting board. Let stand 15 minutes before cutting. Serve warm or at room temperature, cut into squares or wedges.
This and other great recipes can be found in Bob Warden's Favorite Recipes: