I have made this recipe for years. It forms it's own crust.
2 cups fillings of your choice (example broccoli, mushrooms,ham etc.)
1 cup cheese shredded
1/4 cup onion chopped
2 cups milk
1 cup biscuit baking mix (Bisquick) OR Gluten free homemade
OR GF flour + 1 teaspoon baking powder
4 large eggs
1/4 teaspoon salt
1/8 teaspoon black pepper
Bisquick Quiche Recipe Instructions
Heat oven to 400 degrees. Grease 10 inch pie plate or 8 inch square. Sprinkle fillings, onions and cheese in plate. Beat remaining ingredients until smooth and pour into plate. Bake 35 to 40 minutes or until a knife inserted halfway between edge and center comes out clean. Let stand 5 minutes before serving.
I also add whatever is around - spinach, broccoli, ham, bacon, kale.