01 - Preheat oven to 400°F. Lightly oil a baking sheet or line it with parchment paper.
02 - In a large mixing bowl, gently mix ground turkey, breadcrumbs, Parmesan cheese, egg, minced garlic, parsley, oregano, salt, and black pepper until just combined.
03 - Form the mixture into 16 evenly sized meatballs, about 1 1/4 inches in diameter. Arrange them on the prepared baking sheet.
04 - Bake in the preheated oven for 12 to 14 minutes until meatballs are fully cooked and reach an internal temperature of 165°F.
05 - While meatballs are baking, heat marinara sauce in a saucepan over medium heat until hot.
06 - Slice each sub roll lengthwise without cutting all the way through. Lightly toast the rolls in the oven for 3 minutes.
07 - Transfer baked meatballs to the warm marinara sauce and toss gently to coat.
08 - Place 4 meatballs in each sub roll. Spoon extra marinara over the meatballs. Sprinkle with shredded mozzarella cheese.
09 - Return assembled sandwiches to the oven for 2 to 3 minutes until cheese is melted.
10 - Remove from oven, garnish with fresh basil if desired, and serve immediately or pack into containers for meal prep.