Preheat a gas or charcoal grill. (Alternatively, you can cook the patties in a large skillet over medium-high heat.)
In a bowl, combine the beef, garlic, salt, pepper, and Essence, and mix gently but thoroughly. Divide into 8 equal patties.
In a separate bowl, crumble the cheese and form into 4 equal patties. Place 1 cheese patty on each of 4 beef patties. Top with remaining 4 beef patties, pinching the edges under to seal the cheese completely.
Place the stuffed patties on the grill and cook to desired temperature, about 2 to 3 minutes per side for medium-rare. (Alternatively, cook the patties in a large skillet over medium-high heat.) Place the buns on the grill, inside down, until just warmed through, about 30 seconds. Remove the patties and buns from the grill and place on serving plates. Garnish with condiments and serve with the Green Peppercorn Mayonnaise.