Step 1: Prepare the Meatballs : In a large bowl, combine ground turkey, breadcrumbs, Parmesan, egg, garlic, parsley, Italian seasoning, onion powder, salt, and pepper. Mix gently until combined — do not overmix to keep the meatballs tender. Shape into 1 1/2-inch balls (about 12–14 meatballs).

Step 2: Cook the Meatballs : Heat 1 tablespoon olive oil in a large skillet over medium heat. Add the meatballs in batches and cook for 5–6 minutes, turning to brown on all sides. Transfer to a plate (they don’t need to be fully cooked through yet).

Step 3: Make the Marinara Sauce : In the same skillet, add 1 tablespoon olive oil and sauté onion until soft (about 3 minutes). Add garlic and cook for 30 seconds until fragrant. Stir in crushed tomatoes, tomato paste, basil, oregano, red pepper flakes, salt, and pepper. Bring to a simmer, then add the browned meatballs back into the sauce. Cover and cook for 15–20 minutes on low heat until meatballs are fully cooked and sauce thickens.

Step 4: Prepare the Sub Rolls : Preheat oven to 375°F (190°C). Slice rolls in half lengthwise, leaving one edge connected. Spread a little butter on the inside and toast in the oven for 5–7 minutes, until lightly golden.

Step 5: Assemble the Subs : Place 3–4 meatballs inside each toasted sub roll. Spoon extra marinara sauce over the top. Sprinkle generously with mozzarella and Parmesan cheese. Return to the oven and bake until cheese is melted and bubbly (about 5–7 minutes).

Step 6: Serve and Enjoy: Garnish with fresh parsley or basil. Serve hot with a side of salad, fries, or chips.