Heat oven to 375°F.
In small bowl, stir together Bisquick® mix, cheese, garlic powder, 1/4 cup water and the egg; set aside.
In ovenproof 10-inch skillet, cook beef over medium heat about 8 minutes, stirring occasionally, until brown; drain. Stir in spaghetti sauce, 3/4 cup water and the macaroni. Heat to boiling, about 5 minutes, stirring constantly. Spoon Bisquick® mixture around edge of skillet, leaving center open.
Bake 20 to 25 minutes or until top is golden brown. Sprinkle with additional Parmesan cheese if desired.
High Altitude (3500-6500 ft) Increase water for beef mixture to 1 cup. Bake 22 to 27 minutes.
Makes: 5 servings