This chicken parm version of spaghetti and meatballs is lighter than it sounds—perfect for a rainy night!
Preheat the oven to 425°. Line a baking sheet with parchment paper. Bring a large pot of water to a boil for the pasta.
In a food processor, pulse the carrot, celery, onion, and garlic until finely chopped. Heat a large saucepan over medium to medium-high. Add the olive oil, one turn of the pan, then the butter. When the butter foams, add the chopped vegetables; season with salt and pepper. Cover and cook, stirring often, until the vegetables soften, a couple of minutes. Add 1/2 cup water; cook, stirring often, until absorbed, about 5 minutes. Add the passata, half-and-half, and sugar. Stir in the basil. Simmer over low, stirring often, until the sauce thickens and the flavors meld, about 20 minutes.
In a medium bowl, season the chicken with salt and pepper. Mix in the Parm, breadcrumbs, parsley, milk, EVOO, garlic, lemon zest, granulated onion, and nutmeg. Roll the chicken into 1 1/2-inch balls and place on the prepared baking sheet. Roast the meatballs until light golden brown, 12 to 15 minutes.
Salt the boiling water and add the pasta. Cook until 1 minute shy of the package directions. Scoop out about 1/2 cup of the cooking water. Drain the pasta and return it to the pot. Add the butter, Parm, and half the sauce. Add the cooking water if the pasta is too dry.
Add the meatballs to the remaining sauce.
Chop or tear the basil and add to the pasta. Transfer the pasta to a large serving bowl or individual bowls. Top with the meatballs and the remaining sauce.