Cut off a very thin slice from the bottom of the tomatoes.

Grate the tomatoes into a large bowl using the large holes of a box grater. Discard the skins.

Heat a wide pot over medium heat. Once hot, add the sausage and cook, breaking it up periodically, for 12–15 minutes until cooked through. Transfer to a paper towel-lined plate and drain off all but a teaspoon of the oil in the pot.

Melt the butter into the pot and add the onion. Cook for 5–7 minutes until soft. Add the garlic and zucchini and fry for 1–2 minutes. Season with salt, pepper, and a pinch of crushed red pepper to taste.

Return the sausage to the pot and pour in the grated tomatoes. Bring to a boil. Reduce heat and simmer for 20–30 minutes or until the sauce is thick. Stir the sauce occasionally to prevent it from sticking. The grated tomatoes make quite a bit of excess water, so you want to cook it all off! Taste and season with salt and pepper.

Bring a large pot of water to a boil. Once boiling, add a generous amount of salt and the rigatoni. Cook until 1-2 minutes under al dente. Scoop out 1/2 cup pasta water and drain the pasta.

Taste the sauce and season once more. Add the baby spinach, lemon juice, and cooked pasta. Toss to coat for 2–3 minutes until the spinach is wilted. Stir in the Parmesan cheese and toss to coat for 1 minute more. Add pasta water if needed to loosen up the sauce and coat the pasta. Turn off the heat.

Divide the pasta between shallow bowls. Sprinkle more Parmesan on each plate. Enjoy!