Combine Sirloin Steak (2 pound) and Beef Brisket (2 pound) in a large bowl and hand form into 12 oz patties.
Place burgers in freezer for 1 hour to firm.
Prepare grill for indirect cooking at 275 degrees F (140 degrees C), add chunks of hickory wood to coals for smoke flavor.
Caramelize Sweet Onion (1) with Olive Oil (1 tablespoon) in a small sauté pan over medium heat for 15 minutes add Portabella Mushroom Cap (8 ounce) and continue to cook for 4-5 minutes until mushrooms soften. Set aside.
Season each burger on both sides with Killer Hogs The A.P. Rub (1/4 cup) or your favorite all-purpose seasoning.
Place burgers on cooking grate and smoke for 30 minutes.
To make the steak sauce, melt Salted Butter (1 tablespoon) in a small sauce pot over medium heat. Add the Onion (1 tablespoon) and Garlic (3 clove) 1-2 minutes.
Add the Water (4 fluid ounce), Balsamic Vinegar (4 fluid ounce), Worcestershire Sauce (2 fluid ounce), Ketchup (2 ounce), Brown Mustard (2 ounce), Brown Sugar (2 tablespoon), Orange Juice (2 tablespoon), Raisins (2 tablespoon), Chili Sauce (1 tablespoon), Hot Sauce (1 tablespoon), Salt (1 teaspoon) and Ground Black Pepper (1/2 teaspoon), Crushed Red Pepper Flakes (1 pinch) while stirring and bring to a boil.
Lower the heat to a simmer and continue to cook for 10-15 minutes stirring occasionally. Strain sauce and pour into a jar for storage.
Flip burgers and continue to cook until internal temperature reaches 140 degrees F (60 degrees C). Brush Steak Sauce on top of each burger and cook for 1-2 minutes.
Top each burger with mushroom and onion mixture and a slice of Baby Swiss Cheese (6 slice), cook for 30-45 seconds to melt cheese.
To make the roast garlic mayo, combine the Mayonnaise (1 cup), Garlic (6 clove), Lemon Juice (1/2 tablespoon), Salt and Pepper (to taste), store in an airtight container in the refrigerator until ready to serve.
To assemble burger, split a Hamburger Bun (6) and smear Roasted Garlic Mayo on top and bottom.
Place burger patty on the bottom half of each roll and top with 2 slices of Thick-Cut Bacon (12 slice), the top half of the Kaiser roll, and serve.