Light a grill and preheat to medium-high heat.

In a large bowl, combine ground beef and shredded Gouda cheese.

Gently mix until just combined, being careful not to overmix.

Form the mixture into 4 equally sized patties.

Cut the sweet onion crosswise into 1/2-inch thick rounds.

Thread the onion slices onto double bamboo skewers or metal skewers.

Brush the skewered onion slices with vegetable oil.

Season the onion slices with salt and pepper.

Place the skewered onions on the preheated grill.

Grill the onion slices for about 3 minutes per side, or until nicely charred and softened.

Season the beef patties on both sides with salt and pepper.

Place the patties on the preheated grill.

Grill the patties for about 4 minutes per side for medium-rare doneness.

Top each patty with a slice of Gouda cheese.

Cover the grill (if possible) and cook for about 2 minutes, or until the cheese is melted and gooey.

While the burgers are cooking, butter the cut sides of the hamburger buns.

Place the buttered buns cut-side down on the grill.

Grill the buns for about 10 seconds, or until lightly toasted.

Remove the buns from the grill.

On the bottom half of each bun, place a few Bibb lettuce leaves and 2 tomato slices.

Top with the cooked cheeseburgers.

Add the grilled onion slices on top of the cheese.

Spoon some of the Pickled Grilled Peppers over the onions.

Place the top half of the bun on each burger.

Serve immediately, with the remaining pickled peppers on the side.