1Heat oven to 400ºF. Grease 9-inch pie plate. Spread ricotta cheese in pie plate; sprinkle with Parmesan cheese. Cook ground beef until brown; drain. Stir in 1/2 cup of the mozzarella cheese, 1/2 cup spaghetti sauce and the salt; spoon evenly over cheeses.
2Stir Bisquick mix, milk and eggs until blended. Pour into pie plate.
3Bake 30 to 35 minutes or until knife inserted in center comes out clean. Sprinkle with remaining cheese. Bake 1 to 2 minutes longer or until melted. Cool 5 minutes. Serve with additional spaghetti sauce.