Combine Italian Sausage (1 pound), 80/20 Lean Ground Beef (1 pound), Egg (2), Breadcrumbs (1 cup), Grated Parmesan Cheese (1/2 cup), Italian Seasoning (2 teaspoon), Granulated Garlic (1 teaspoon) and Crushed Red Pepper Flakes (1/2 teaspoon) together in a large bowl with wet hands (or gloves). Once all ingredients are well combined, roll into balls that are about the size of a golf ball.
Place the meatballs on a pork rack sprayed with non-stick cooking spray. You can smoke your meatballs on any grill or smoker. You want to hold the temps at 275 degrees F (140 degrees C) with a little light smoke. Allow the meatballs to smoke for 35 - 45 minutes - or until the meatballs hit an internal temp around 160-165 degrees Fahrenheit (71-73 degrees C).
Heat Olive Oil (2 tablespoon) in a large pot and cook Onion (1) until softened. Add Garlic (2 clove) and cook for 2 minutes. Add Italian Seasoning (2 teaspoon), Salt (1 teaspoon), Caster Sugar (1/2 tablespoon), Frank's® RedHot® Sauce (1 tablespoon), Parmesan Cheese (1/3 cup), Chicken Broth (1 cup), Canned Crushed Tomatoes (28 ounce) and Canned Tomato Purée (28 ounce). and bring to a simmer. Cook over low heat for about an hour or until sauce thickens.
Once the Meatballs are brown and smoked, pull them off and add them to a small pan and cover with your Marinara Sauce.
Place the pan back on the smoker with the meatballs and sauce - holding steady at 275 degrees F (140 degrees C) - for about 15 minutes. Then you want to cover the pan with foil and allow it really cook and get warm, hot and bubbly. You need to cook it covered for another 30-40 minutes.
Once your meatballs have reached an internal of 165 degrees F (73 degrees C) and the sauce is hot, it's time to assemble your Smoked Italian Meatball Subs.
Use mini sub rolls and thin sliced provolone cheese, then add your meatballs and sauce and top with a little extra provolone cheese.