Place all ingredients, except buns and toppings, in a bowl and mix to combine. With cold-water moistened hands, shape the meat into 8, 3/4" thick patties. Preheat your barbecue to medium-high. Place the toppings in bowls and small plates.
Grill the burgers for about 4 minutes per side, or until entirely cooked through and the centre of each burger reaches 160 degrees F (71 degrees C) on an instant read meat thermometer.
Set the burgers out on a platter with the buns and toppings nearby and let your guests build their own burger.
Recipe Options: Use a mix of ground beef, pork and veal to make the burgers. Make a chipotle mayonnaise to spread on the buns by combining 1/2 cup mayonnaise, 2 finely chopped chipotle peppers, pinch sugar, 2 Tbsp. lime juice, 2 Tbsp. chopped fresh cilantro or green onions, and salt to taste. Cover and store in the fridge until needed. Chipotle peppers (smoked jalapenos) are sold in tins in the aisle with Mexican foods. Unused peppers, which can be used in chili, taco mixes and barbecue sauces, can be stored in a tight-sealing jar in the fridge.