Gently but thoroughly mix together the ground beef and ground Italian sausage (removing from the casings if any), along with the Italian spices, chopped onion, chopped Bell pepper and 2 cloves of minced garlic.
Press the mixture into a jelly roll pan using a rolling pin to make a flat even layer.
Cut the meat into 2″ squares using a a 2 inch spatula.
Grill 2-3 minutes on each side or until cooked through to a temperature of at least 165. If you prefer the cheese melted, place on top during the last minute or two of cooking.
If not fresh from the oven, wrap the rolls in foil and warm on the top rack of the grill while the burgers are cooking on their second side. I use frozen white parker roll dough but you could make your own.
When the burgers are done, place a slice of mozzarella on each burger and tent with foil while preparing the buns.
Whisk together olive oil, balsamic and remaining 1 clove minced garlic
Place the burger with cheese on the bottom of the bun, add a slice of tomato and two good-sized basil leaves and drizzle each burger with 1/2 teaspoon of the balsamic/olive oil dressing.