1/2 cup butter
3 cloves garlic, chopped
1 small onion, chopped
10 ounces frozen chopped spinach, thawed and drained well
1 4.5-ounce can mushrooms, drained
1 6-ounce package herb and garlic feta cheese, crumbled
8-ounce package cheddar cheese, shredded
Salt and pepper to taste
1 unbaked 9-inch deep-dish pie crust
4 eggs, beaten
1 cup milk
Preheat oven to 375 degrees. In a medium skillet, melt butter over medium heat. Sauté garlic and onion in butter until lightly browned. Stir in spinach, mushrooms, feta and 1/2 cup cheddar cheese. Season to taste with salt and pepper; spoon mixture into pie crust.
In a medium bowl, whisk together eggs and milk. Season with salt and pepper. Pour into the pie crust, allowing egg mixture to thoroughly combine with spinach mixture.
Bake for 15 minutes at 375 degrees. Sprinkle top with remaining cheddar cheese and bake an additional 35 to 40 minutes until set in the center. Allow quiche to stand 10 minutes before serving.