Brown the sausage: Heat olive oil in a large deep skillet over medium-high heat. Add the sausage, breaking it up with a spoon, and cook until browned with crispy edges, about 5–7 minutes. Transfer to a plate, leaving a little fat in the pan.

Sauté the aromatics: Add onion and bell pepper to the same skillet. Cook 3–4 minutes until softened. Stir in zucchini and cook another 2 minutes. Add garlic and cook 30 seconds until fragrant.

Build the sauce: Stir in crushed tomatoes, tomato paste, Italian seasoning, red pepper flakes, and a pinch of black pepper. Let it bubble for a minute to marry the flavors.

Add pasta and broth: Pour in the chicken broth and bring to a gentle boil. Add the dry pasta and stir so it’s submerged. Reduce heat to medium, cover, and simmer 9–11 minutes, stirring once or twice to prevent sticking.

Return the sausage: When the pasta is al dente and most liquid is absorbed, add the browned sausage back to the skillet. Toss to combine and cook 1–2 minutes more. If the skillet looks dry, add a splash of broth or water to loosen.

Fold in greens: Stir in spinach or kale until just wilted, about 1 minute. Taste and season with salt if needed.

Finish and serve: Turn off the heat. Stir in Parmesan and a squeeze of lemon. Top with fresh basil or parsley. Serve hot with extra Parmesan and a crack of black pepper.