Heat the olive oil in a skillet over medium heat. Add the sliced onions and cook, stirring often, until they turn golden and soft, about 15 minutes. Set aside half the onions for topping later.
Chop 4 slices of bacon into small pieces. In a mixing bowl, combine the ground beef, chopped bacon, egg, smoked paprika, salt, pepper, and 1/4 cup of the BBQ sauce. Mix until just combined.
Divide the mixture into four equal portions and shape each into a small loaf. Place the loaves on a baking sheet lined with parchment paper.
Brush the top of each loaf with the remaining BBQ sauce. Lay the remaining 2 slices of bacon across the tops, then spoon the reserved caramelized onions over each loaf.
Bake at 375 degrees for 25 to 30 minutes, until the internal temperature reaches 160 degrees. Let the loaves rest for 5 minutes before serving.