Bring a large pot of water to a rapid boil. Add 1 tablespoon salt. Add the dried pasta and cook according to package instructions until al dente (usually 9–12 minutes depending on shape). Reserve 1 cup of the starchy pasta cooking water, then drain pasta and set aside.

Sauce base

Cook aromatics

While pasta cooks, heat a large heavy skillet over medium heat. Add 2 tablespoons olive oil and 1 tablespoon butter. When butter melts and foams, add the diced onion and a pinch of salt. Sauté until translucent, about 4–5 minutes. Add the sliced mushrooms and zucchini, cook until softened and starting to brown, 4–6 minutes. Add the minced garlic and sun-dried tomatoes and cook 30–60 seconds until fragrant.

Cook protein

Push vegetables to one side and add the Italian sausage (remove casings if using link) or ground chicken/turkey. Break it up with a spatula and cook until browned and cooked through, about 6–8 minutes. Season lightly with pepper and a pinch of salt. Mix with the vegetables.

Build the sauce

Stir in the tomato paste and cook 1 minute to remove raw edge. Add the crushed tomatoes, 1 cup stock, dried oregano, dried basil, red pepper flakes (if using), and sugar. Bring to a gentle simmer, then reduce heat to low and simmer, uncovered, for 10 minutes to meld flavors.

Vegetables & additions

After the sauce has simmered 10 minutes, stir in the baby spinach in batches until wilted. Taste and adjust seasoning with additional salt/pepper if needed.

Finishing & garnish

Lower heat to very gentle. Stir in 1 cup heavy cream and 3/4 cup grated Parmesan into the sauce until melted and smooth. If the sauce is too thick, add some reserved pasta water, 2 tablespoons at a time, until you reach a saucy consistency that will coat the pasta (about 1/2 to 1 cup).

Add the drained pasta directly into the skillet (or return sauce to the pot and add pasta). Toss thoroughly over low heat for 1–2 minutes to marry pasta with sauce and allow starch to thicken the sauce. Stir in chopped fresh basil and adjust seasoning with freshly ground black pepper and salt to taste. If desired, sprinkle additional Parmesan when serving.