Pre-heat oven to 350 degrees.

Slice each bacon slice in half crosswise and lightly season with pepper on both sides.

Place a wire rack on a sheet pan and lay bacon on wire rack.

Cook bacon for 15 minutes, then flip and cook for an additional 10 minutes until golden brown.

On medium heat, add grapeseed oil and onions and sauté continuously for 10 minutes.

Add bourbon, honey, brown sugar, and apple cider vinegar and sauté for another 3 minutes until reduced to 1/3 in volume and syrupy; season with a pinch of salt and pepper and cool to room temperature.

Thaw burgers in refrigerator overnight, then bring to room temperature on counter for about 15 to 20 minutes.

Gently flatten burgers out to about 1/2” thickness and generously season only one side of burger patties with salt and pepper, leaving the other side unseasoned.

Flip two burger patties seasoned side-down and place two slices of fontina cheese in the middle of the patties.

Top with the other two burger patties seasoned side-up, pressing and sealing the edges to secure the cheese in the center.

In a large cast-iron pan on medium-high heat, add vegetable oil and cook stuffed burgers 3 minutes on one side.

Add butter to pan, flip burgers, and butter baste for 30 seconds.

Continue to cook burgers for two minutes.

Top each patty with a slice of fontina cheese, add water to pan, and cover with lid; cook for 30 to 45 seconds until cheese is melted.

Remove burgers from pan.

Add about 1 tablespoon of mayonnaise to each side of bun and toast on medium-high heat in a clean pan until golden brown.

Assembly: Add ketchup, mustard, and mayonnaise to each side of burger buns. Add about 2 spoonfuls of onion jam to bottom bun, then top with three pickles, then the stuffed burger, then four bacon halves, then half a handful of potato chips, and finish with the top bun.