Heat oven to 375°F. Spray 12 regular-size muffin cups with cooking spray. Step 2 In 10-inch skillet, cook beef and onion over medium-high heat 5 to 7 minutes, stirring frequently, until thoroughly cooked; drain. Cool 5 minutes; stir in Worcestershire sauce, garlic salt and cheese. In medium bowl, stir baking mixture ingredients (½ cup milk, ½ cup Original Bisquick® mix, 2 eggs) with whisk or fork until blended. Spoon 1 scant tablespoon baking mixture into each muffin cup. Top with about ¼ cup burger mixture. Spoon 1 tablespoon baking mixture onto burger mixture in each muffin cup. Bake about 30 minutes or until toothpick inserted in center comes out clean, and muffin tops are golden brown. Cool 5 minutes. With thin knife, loosen sides of muffins from pan; remove from pan and place top side up on cooling rack. Cool 10 minutes longer, and serve with garnishes (mini kosher dill pickles, tomato, ketchup and mustard). This recipe was shared by Bisquick®.