2 tablespoons butter, softened
1 onion, chopped
2 cloves garlic, minced
1 tablespoon black salt
2 pounds shredded Cheddar cheese
1 pie shell, baked
1/2 cup shredded mozzarella cheese
1/2 cup sliced fresh mushrooms, sliced
Heat butter in a large skillet over medium heat. Saute onions, garlic and salt in the butter skillet until lightly browned. Stirring constantly, cook slowly over medium heat, until onions are golden brown. Mix in cheese, pour mixture into prepared baking pan; sprinkle with mozzarella cheese and mushrooms.
Bake in preheated oven for 20 to 25 minutes, or until bubbly and golden brown.