In a large bowl, combine ground chicken, grated apple, bread crumbs, beaten egg, chopped onion, salt, and black pepper. Mix well until all ingredients are evenly incorporated.
Form the mixture into 4 equal-sized patties.
Heat a grill or skillet over medium heat and cook the patties for about 5-7 minutes on each side or until fully cooked and golden brown.
Serve the apple chicken burgers on buns with your favorite toppings and condiments.
Notes
For added flavor, try adding a slice of cheddar cheese and a dollop of honey mustard sauce.