Get your grill/pan/etc hot for the burgers.
Mix ground beef, Italian sausage, and pizza seasoning (oregano, basil, marjoram, garlic) together. Divide into 8oz (1/2 lb) portions (or you can use smaller 6oz portions). Flatten into patties that are about 1/2 inch larger than the buns.
Put a thumbprint in the middle of the patty so it doesn’t puff up when cooking.
Grill your burgers about 4min on the first side.
While burgers are grilling, heat marinara sauce in a pan on med-low heat until warm. Heat pepperoni on a pan or on tinfoil on the grill for a couple minutes.
Flip burgers and cook until you reach the correct temp (140F for medium), usually about 2 to 4 minutes. Top burger with sliced cheese about a minute before taking off the grill.
Place buns face down on the grill for a minute or two to toast.
Add burgers to buns, spoon on marinara, add pepperoni & sprinkle with parmesan cheese. Enjoy!