01 - In a large bowl, gently mix ground turkey, egg, breadcrumbs, milk, parsley, grated onion, minced garlic, oregano, salt, and pepper until just combined; avoid overmixing.
02 - With damp hands, shape the mixture into 16 golf ball-sized portions.
03 - Heat 2 tablespoons of olive oil in a large skillet over medium heat. Brown meatballs in batches, turning gently until golden on all sides, about 5 to 7 minutes. Remove and set aside.
04 - In the same skillet, add 2 tablespoons olive oil and sauté the chopped onion until softened, about 3 minutes. Add garlic and cook an additional minute until fragrant.
05 - Stir in crushed tomatoes, dried basil, oregano, sugar, salt, and pepper. Bring to a gentle simmer.
06 - Nestle meatballs carefully into the sauce. Cover and simmer over low heat for 25 to 30 minutes until meatballs are fully cooked and sauce thickens.
07 - Adjust seasoning as needed. Garnish with fresh basil or parsley before serving.