Preheat a gas grill over high heat or a charcoal grill until it glows bright orange and ashes over.

In a large bowl combine the ground beef and Italian sausage. Shape the mixture into six patties.

Grill the burgers until browned and slightly charred on the first side (about 3-4 minutes). Flip the burgers over and continue to cook until desired doneness - about 4 minutes for medium rare, longer for a more done burger.

Meanwhile, butter the cut sides of the ciabatta rolls and toast on grill. Keep an eye on them - it won't take long.

To assemble the burger, spoon about 2-3 tbsp. of the spaghetti sauce onto the cut part of the bottom portion of the ciabatta rolls. Place one of the cooked burger patties on top. Add a slice of cheese. Top each burger with six slices of pepperoni. Replace the top portion of the bun. Serve!