Cheeseburger Muffins - Recipook

Ingredients

• cooking spray (such as Pam®)
• 1 pound ground beef
• 1 small onion, chopped
• 2.5 cups all-purpose flour
• 1 tablespoon white sugar
• 2 teaspoons baking powder
• 1 teaspoon salt
• 0.75 cup ketchup
• 0.75 cup milk
• 0.5 cup butter, melted
• 2 eggs, beaten
• 1 teaspoon prepared yellow mustard
• 2 cups shredded Cheddar cheese