Preheat grill to medium.
In a bowl, combine beef, garlic, hot sauce, salt and pepper to taste, being careful not to overmix. Warm a skillet over medium heat and fry bacon until crispy. Remove to a paper towel-lined plate to drain.
Keep heat on skillet and fry a pinch of the beef in the bacon fat to test seasoning. Adjust seasoning, if needed, then form 8 even, thin patties, about 1/2-inch thick and set aside.
Saut onions in bacon fat in skillet until tender, 5 minutes. Place onions and bacon in a bowl with cheese. Form a spoonful of bacon-cheese mixture into a ball, then place in the center of 4 patties. Top each with another patty and seal the edges.
Grill burgers over medium-high heat, flipping once until desired doneness is reached, or sear in a medium skillet over medium-high heat approximately 4 minutes each side for medium. Serve in buns with garnishes.