1Heat oven to 450°F. Spray 12 regular-size muffin cups with cooking spray.
2In 10-inch nonstick skillet, cook beef and onion over medium-high heat 5 to 7 minutes, stirring occasionally, until thoroughly cooked; drain. Stir in barbecue sauce; cook until mixture just begins to bubble.
3In medium bowl, stir Bisquick mix, 1/2 cup of the cheese and the milk until soft dough forms. Spoon about 2 tablespoons dough into each muffin cup. Press dough in bottom and up sides of each cup. Spoon 2 tablespoons beef mixture into each cup.
4Bake 8 to 10 minutes or until top edges of cups are golden brown. Sprinkle each with remaining cheese. Let stand 5 minutes; remove from pan.