Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper if desired.
In a large mixing bowl, combine the ground turkey, breadcrumbs, grated Parmesan cheese, egg, chopped parsley, minced garlic, onion powder, Italian seasoning, salt, and black pepper.
Use your hands or a spoon to mix the ingredients until just combined. Avoid overmixing to ensure tender meatballs.
With wet hands, shape the mixture into approximately 12 meatballs, about 1.5 inches in diameter.
Place the meatballs on the prepared baking sheet, spaced evenly apart.
Bake in the preheated oven for 20-25 minutes, or until the internal temperature reaches 165°F (74°C) and the meatballs are cooked through.
While the meatballs are baking, warm the marinara sauce in a saucepan over medium heat.
Once the meatballs are done, serve them with the warm marinara sauce. They can be served over pasta, in a sandwich, or on their own.