It's traditional to serve a burger on a sliced and toasted bun with ketchup, mustard, pickles, lettuce, sliced tomato, cheese (use dairy-free cheese if you're on a dairy-free diet), and sometimes bacon. You can use any, all, or none of these toppings on your burger as it is really just personal preference. u003cbr/u003eu003cbr/u003eIn the United States, we often serve our burgers with a buffet of choices to allow everyone to pick their own toppings.