Whisk together mustard and mayonnaise in medium bowl; set aside.
CCP: Maintain cold food at 41°F or below
Layer bottom bun halves with beef patty, ham slice and cheese slice.
Lightly spread cut side of top bun halves with mustard-mayonnaise mixture. Place on burger. Serve immediately.
CCP: Maintain hot food at 140°F or above
Serve with dill pickle slices as optional topping.