Heat a grill to medium-high.
For the bacon jam: Place the bacon, onion, syrup, mustard, apple cider vinegar, sugar, garlic, pepper and salt in a food processor and blend until smooth with no lumps.
For the peanut butter burgers: Cook the patties on the grill until they have almost reached your desired level of doneness. While still on the grill, add a slice of cheese and a tablespoon of bacon jam to each patty, covering the patties for about 20 seconds to melt the cheese.
Toast the buns, then spread mayonnaise on the top half and peanut butter on the bottom half of each. Place the burgers on the buns, followed by a small handful of lettuce and a few slices of tomato and pickle.