Grease muffin tin with nonstick cooking spray and fill 5 moulds with beef mixture.
Bake for 40-50 minutes to desired doneness (oven time will vary somewhat).
During the last 3 minutes of baking, sprinkle cheese on top.
In a small bowl, combine ketchup and mayonnaise and mix well. Put sauce on each burger and top with a pickle and sesame seeds to garnish. Enjoy the Whopper Bites!