CHEESEBURGER QUICHE

1 lb. browned ground beef
5-6 cups shredded cheese (cheddar & mozzarella)
10 large eggs
1 cup milk
1 cup mayonnaise
1 1/2 cups whole wheat flour
1 tsp. salt
1 tsp. Oregano
1 cup chopped onion (optional)

Mix eggs, milk, mayonnaise, flour, salt, and oregano in large bowl. Layer beef, cheeses and onion in a greased 9x13 baking dish. Pour egg mixture over beef, cheese, and onion. Let sit for 15 minutes. Bake at 350 degrees for 50 minutes or until golden brown and knife inserted in the center comes out clean.