Turkey Spinach Meatball Subs

Prepare the Meatballs
1 Preheat the oven to 350°F. Prepare a baking sheet -- line it with parchment paper, aluminum foil or a silpat mat. Spray with cooking spray, and set aside.
2 In a large glass bowl, combine the ground turkey, cooked spinach, onion, garlic cloves, panko breadcrumbs, Parmesan, egg and spices using your hands.
3 When the meatball mixture has come together and is well mixed, prepare the meatballs. Using a small cookie scoop, form the meatballs with your hands, then place carefully on the baking sheet. Repeat the process until all the mixture has been made into meatballs.
4 Bake the meatballs for 30-40 minutes, or until browned on the outside and cooked through in the middle.
Prepare the Marinara Sauce
1 While the meatballs are baking, heat the olive oil in a Dutch oven over medium-high heat.
2 Add the onion and garlic, cooking for 2-3 minutes, or until the vegetables have become translucent.
3 Pour in the tomato puree and water, stirring until combined. Add the tomato paste and the spices, and bring to a boil.
4 Once at a boil, lower heat to a simmer and partially cover, simmering until the meatballs have finished cooking.
Combine the meatballs and marinara
1 When the meatballs have finished cooking, transfer them directly into the marinara sauce.
2 Simmer the sauce and meatballs for an additional 30 minutes.
Prepare the sandwiches
1 Toast the bread.
2 Slice the bread in half, and place the fresh mozzarella down first on the bottom slice.
3 Gently spoon meatballs and marinara sauce on top of the mozzarella, then top the sandwich with the other half of the bread.
4 Enjoy warm!