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.