Combine coffee rub seasoning mix ingredients in a small bowl and mix together with a fork. Set aside.
Melt butter over medium heat in a saucepan. Add onion and garlic and sauté until soft and translucent, about 8-10 minutes.
Add remaining sauce ingredients, stir to combine. Bring to a low boil, reduce heat and simmer for 20 minutes, until sauce has thickened.
Pour sauce into blender or food processor and puree. Set aside to cool.
To a mixing bowl, add ground beef, salt, pepper and 2 Tbsp cooled bbq sauce. Mix well with your hands. Divide into 4 equal sections. Each burger will be 1/2 pound.
Rub coffee rub seasoning mix over both sides of each burger.
Heat a large skillet, add a small pat of butter and toast the buns. Remove from pan to cool.
Add 1 Tbsp butter to skillet and add burgers. Cook for about 4-5 minutes per side, until burger is cooked to desired doneness.
Spread BBQ sauce over both sides of the bun, layer lettuce, burger, bacon, then add the top bun.