In a large mixing bowl add sirloin, egg, 2 tbsp. of rub, bread crumbs and diced jalapeno. Mix thoroughly and shape into 8-10oz patties (fit to be a bit bigger than your bun). Press a slight thumb print into center of the patty to help even cooking.
Heat your grill to medium high (300-500°F). For best results use charcoal. Cook for approximately 4-5 minutes per side.
In a pan, heat the butter. Once hot, sautee onion and jalapeno until the onions are translucent.
Once the burgers reach a temperature of 150, add 1 tbsp. of grated chocolate to the top of each burger and top with cheese.
Let the burgers rest about 2-3 minutes, top with onion and jalapenos, serve and enjoy!