Preheat the oven to 375°F. Line a large baking sheet with foil and place a baking rack on top (a cooling rack works well too).
In a small bowl, combine brown sugar and black pepper.
Arrange bacon strips on the rack. Evenly sprinkle the sugar mixture over the bacon.
Bake for 20-25 minutes, turning the pan halfway through the cooking time.
Once done, take the pan out of the oven and let the bacon cool on the rack.
In a medium skillet over medium-low heat, melt the butter. Add the sliced onions, salt, and sugar. Cook for 20-25 minutes until the onions are golden and tender.
Combine all BBQ sauce ingredients in a small saucepan. Bring to a boil, then reduce the heat and simmer for 20-30 minutes, stirring often. Allow the sauce to cool.
Mix the ground beef with salt and pepper in a bowl. Divide into 8 portions and shape into patties.
Grill the patties for 4-5 minutes per side.
Top each burger with a slice of cheddar cheese and let it melt. Remove from the grill and assemble with BBQ sauce, caramelized onions, and candied bacon.