Heat 1 tablespoon olive oil in a large saucepan over medium heat. Add 1 chopped medium onion and sauté until translucent, about 3 minutes, then add 4 minced garlic cloves and cook 1 more minute.
Add the 28-ounce can crushed fire-roasted tomatoes (with liquid), 3 tablespoons tomato paste, 2 teaspoons chopped fresh oregano, 1 teaspoon minced chipotle in adobo, 1 sprig rosemary, and a pinch of salt. Bring to a low boil, then reduce heat and simmer about 15 minutes until the sauce has reduced slightly.
Taste the sauce and adjust seasoning with salt and freshly ground black pepper as needed. Keep sauce at a low simmer while you prepare the meatballs.
Preheat the broiler and lightly spray or oil a baking sheet.
In a large bowl combine 1 pound ground turkey, 1 slice whole-wheat bread pulsed into crumbs, 1/4 cup grated Parmesan, 1/2 cup grated carrot, 1/2 cup finely chopped onion, 2 minced garlic cloves, 2 tablespoons minced parsley, 2 teaspoons minced thyme, 1 lightly beaten large egg, 1/2 teaspoon salt, and freshly ground black pepper. Mix until just combined.
Form the mixture into about 2½-inch meatballs and arrange them on the prepared baking sheet. Broil for about 10 minutes, until browned and almost cooked through.
Remove the rosemary sprig from the simmering sauce and stir in 1/4 cup torn fresh basil leaves.
Add the broiled meatballs to the sauce, cover, and simmer an additional 10 minutes until the sauce thickens slightly and the meatballs finish cooking.
Meanwhile, bring a large pot of salted water to a boil and cook the 16 ounces whole-wheat spaghetti according to package directions. Drain and return to the pot.
Add the sauce and meatballs to the drained pasta, toss gently, and heat through over medium heat. Divide among 6 bowls and garnish with additional parsley and about 1 tablespoon grated Parmesan per serving, if desired.