Ingredients

1 pound lean ground beef (90% lean)1/3 cup ketchup2 tablespoons prepared mustard1/2 teaspoon salt1 large onion4 ounces cheddar cheese, cut into 8 squares3/4 cup all-purpose flour2 teaspoons garlic powder2 large eggs, lightly beaten1-1/2 cups panko bread crumbsCooking spraySpicy ketchup, optional

Preparation

Preheat air fryer to 335°. In a small bowl, combine beef, ketchup, mustard and salt, mixing lightly but thoroughly. Cut onion into 1/2-in. slices; separate into rings. Fill 8 slices with half of the beef mixture (save remaining onion rings for another use). Top each with a square of cheese and remaining beef mixture.

In a shallow bowl, mix flour and garlic powder. Place eggs and bread crumbs and eggs in separate shallow bowls. Dip filled onion rings in flour to coat both sides; shake off excess. Dip in egg, then in bread crumbs, patting to help coating adhere.

In batches, place onion rings in a single layer on greased tray in air-fryer basket; spritz with cooking spray. Cook until golden brown and a thermometer inserted into beef reads 160°, 12-15 minutes. If desired, serve with spicy ketchup.