Preheat oven to 350. Saute onions, mushrooms, garlic in a small amount of olive oil or butter.Meanwhile combine cracker crumbs and melted butter in 9 inch deep dish pie plate, pressing firmly onto sides and bottom. When onion is translucent,slide all of it (including added veggies or meats) into crust. Combine milk, eggs, salt and pepper, and pour over evenly. Top with cheese. Sprinkle with paprika, and bake for 30 minutes, or until set and knife comes out clean.