Chicken patties: grind your own chicken in a food processor or meat grinder. You can also purchase ground chicken from the store if you can find it. If you've never processed ground chicken before and you own a food processor, chop the meat into small 1/2-inch pieces and add to a food processor, pulse until you have a paste of chicken with no large pieces.

Grab a small bowl and pour 1/2 to 1 cup of water into it. You will be using this to dip your hands/fingers in while you're shaping patties, and the water helps your hands not to stick to the chicken as much.

In a large bowl, add ground chicken, sugar, salt, garlic powder, onion powder, and MSG (if using). Wet your hands and use them to mix up all the chicken and spices. Your hands are the best tool for this, and you will have to use them again in shaping your patties. 

Once everything is combined, it is time to shape. Split the ground chicken mixture into 4 equal-sized portions. These should all be about a quarter of a pound each. 

Line a sheet pan with parchment and spray with non-stick baking spray if you want. This will help the patties not stick to the surface as much, but it's optional. Take one portion of the chicken mixture and scoop it onto the parchment. With wet hands, you can shape the chicken mixture into a 7-inch by 3-inch rectangle. Do this for all 4 portions of the chicken mixture. I found that you'd want your raw chicken patties to be about a quarter to a half inch thick. 

Once your patties are formed, they need to go into the freezer to firm up. You can freeze them for an hour, and then, if you want, you can remove them from the sheet pan and package them up in freezer-safe bags and store them in the freezer until you plan to use them. I wouldn't store them for more than a few months, but a couple of weeks in the freezer should be just fine. 

When you are ready to fry your patties, add at least 2 inches of oil to a large pot and set it on medium-high heat on your stove. Now you need to make the dredge and coat each patty.

Chicken patty frying: set up your chicken dredging station. You will need three bowls or large plates for this. 

The first bowl will contain all-purpose flour. Add 1/2 teaspoon salt and 1/2 teaspoon black pepper to the flour. The second bowl will contain 2 whole eggs whisked thoroughly. The third bowl will have Panko breadcrumbs, 1 teaspoon salt, 1/2 teaspoon black pepper, and 1 teaspoon of paprika. Whisk to combine. 

Once your oil is heated up to 350 degrees F, it's time to dredge and fry. 

Working one patty at a time, carefully coat it in the seasoned flour, then into the whisked egg, and finally in the seasoned Panko bread crumbs. During each step, make sure the patty is fully coated. When you are done, place each patty on a cooling rack or cutting board while you finish the other patties. 

Fry 2 patties at a time in the hot oil for 3 minutes per side or until the exterior is golden and crispy. Remove the patties to a clean cooling rack while you finish frying the other patties. 

Sandwich assembly: spread a tablespoon or two of marinara on the bottom of the roll and top it with a fried chicken patty.

Arrange 2 or 3 slices of mozzarella on top of the chicken, and place the bottom side and top side of the roll face up under the oven broiler or in a 350°F (175°C) oven until the cheese melts just a little bit and the top slice of the roll is a little bit toasted. 

Add more marinara on top of the melty cheese and then close the sandwich, serve, and enjoy.