Spinach Breakfast Casserole
1/2 cup chopped onion 4 garlic cloves, minced 1 tablespoon butter 8 eggs 1 10 oz. package frozen chopped spinach, thawed and squeezed dry 1-1/2 cups (6 ounces) shredded mozzarella cheese 1 cup (4 ounces) crumbled blue cheese, divided 2 plum tomatoes, diced 1 plum tomato, sliced, optional Combine onion,…