12 ounces (¾ pound) lean ground beef
3 tablespoons minced onion
4 teaspoons ketchup
2 teaspoons yellow mustard
salt and freshly ground black pepper
4 slices of Cheddar cheese, broken into smaller pieces
8 hamburger dill pickle chips
Combine the ground beef, minced onion, ketchup, mustard, salt and pepper in a large bowl. Mix well to thoroughly combine the ingredients. Divide the meat into four equal portions.
To make the stuffed burgers, flatten each portion of meat into a thin patty. Place 4 pickle chips and half of the cheese onto the center of two of the patties, leaving a rim around the edge of the patty exposed. Place the remaining two patties on top of the first and press the meat together firmly, sealing the edges tightly. With the burgers on a flat surface, press the sides of the burger with the palm of your hand to create a straight edge. This will help keep the stuffing inside the burger while it cooks.
Pre-heat the air fryer to 370 degrees F.
Place the burgers inside air fryer basket and air-fry for 20 minutes, flipping the burgers over halfway through the cooking time.
Serve the cheeseburgers on buns with lettuce and tomato.