Step 1

Preheat the oven to 400 degrees F.

Step 2

For the meatballs: In a large bowl, combine the breadcrumbs, Parmesan, basil, parsley, milk, ketchup if using, tomato paste, salt, pepper, eggs, garlic and onions. Using a wooden spoon, stir to blend. Add the ground turkey and sausage meat. Using fingers, gently mix all the ingredients until thoroughly combined.

Step 3

Using a 1-ounce cookie scoop or a small ice cream scoop, form the meat mixture into 1 1/2-inch balls (22 to 24 meatballs). Place the meatballs on a heavy nonstick baking sheet, spacing apart. Drizzle with olive oil and bake until cooked through, 15 minutes.

Step 4

For the tomato sauce: Heat the olive oil in a large deep skillet with 2-inch-high sides over medium-high heat. Add the garlic, onions, salt and pepper. Cook for 5 to 6 minutes. Add 1/2 cup of the basil, the fennel, oregano and crushed tomatoes. Bring to a simmer. Cook over medium heat until the sauce thickens slightly, stirring occasionally, 15 to 20 minutes. Stir in the remaining 1/4 cup basil. Adjust the seasoning with more salt and pepper if desired.

Step 5

Add the meatballs to the tomato sauce and simmer until the meatballs are heated through, about 10 minutes. Thin the sauce with chicken stock, 1/4 cup at a time, if needed.

Step 6

Serve with grated Parmesan alongside.