Preheat the grill. In a bowl, mix the meat. Form 4 (3-ounce) patties by using a scoop. Push them down and make little indentations in the middle to hold the flavors. Place a chunk of mozzarella and drizzle some chili paste or chili flakes on top of the mozzarella. Add a good twist of black pepper. Take another 3-ounce scoop of meat, make it flat in your hand and place right on top of the other half.
Take your fingers and just seal the 2 patties up and refrigerate until you are ready to grill.
Meanwhile: Split the pieces of bread, and pull out some of the soft center to make a hole for the burger. Place the bread face down on the grill to toast.
Place the burger in the bread, and top with your favorite condiments.