In a large mixing bowl, combine ground turkey, egg, breadcrumbs, Parmesan, garlic, parsley, oregano, onion powder, salt, and pepper. Mix until uniform and slightly sticky, about 2-3 minutes.

Scoop portions of the turkey mixture and roll them into meatballs, approximately 1 to 1.5 inches in diameter, aiming for 16 to 18 meatballs total.

Heat olive oil in a large skillet over medium heat. Once hot, add the meatballs and cook for 2-3 minutes on each side until golden brown.

Pour marinara sauce into the skillet, ensuring the meatballs are fully coated. Cover and let it simmer for 12-15 minutes on low heat.

Preheat your broiler. Split the rolls and place them on a baking sheet, cut side up. Toast under the broiler for about 60-90 seconds.

Remove meatballs from heat and load them into the toasted rolls, topping with mozzarella cheese.

Return the assembled subs to the broiler for 2-4 minutes, until the cheese is melted and bubbly.

Garnish with fresh basil, cut subs in half for easy serving, and enjoy!