Recipe courtesy of Tyler Norby, finalist of the 2020 Blended Burger Project Home Edition Competition.
Broil bacon until crisp, flipping once, and set aside.
Make the rub by whisking together all rub ingredients to mix thoroughly and set aside.
Gently fold together beef and white button mushrooms. Then fold in the minced garlic, finely diced red onions, Worcestershire sauce, 1 tablespoon ketchup, Parmesan cheese, and 3/8 cup of the rub mix.
Form beef mixture into 6 patties. The patties should be approximately 3/4 to 1 inch thick. Take Kosher salt and evenly sprinkle 1/4 teaspoon per side of each beef patty, gently patting the salt into the patty with your fingertips. Rub both sides of each patty with the remaining rub mix. Pierce through the center of each patty one time with a thin knife.
Use direct heat for charcoal barbecuing or medium-high heat for propane barbecuing. Grill on first side for 5 minutes with the lid closed. Flip patties and layer them with one piece of maitake mushrooms, 2 bacon pieces, 1 slice of Jarlsberg cheese, and 1 slice of Gruyere cheese. Close lid and grill for 4 more minutes.
Remove the patties from the barbecue and allow them to rest for 2 minutes.
Assemble hamburgers as follows, from bottom to top: bottom bun, 1 teaspoon mayonnaise, 1 slice of lettuce, 1 grilled beef patty, 4 pickle slices, 1 slice of red onion, 1 slice of tomato, 1 teaspoon yellow mustard, 2 teaspoons ketchup, top bun.