Barbecue Muffins
["1 (10 oz.) can refrigerated buttermilk biscuits", "1 lb. ground chuck", "1/2 c. ketchup", "3 Tbsp. brown sugar", "1 Tbsp. cider vinegar", "1/2 tsp. chili powder", "1 c. (4 oz.) shredded Cheddar cheese", "1/2 c. chopped onion (optional)"]
["Separate dough into 10 biscuits.", "Flatten into 5-inch circles. Press each into the bottom and up sides of a greased muffin pan; set aside."]
["buttermilk", "ground chuck", "ketchup", "brown sugar", "cider vinegar", "chili powder", "Cheddar cheese", "onion"]