Start by boiling a large pot of salted water. Once boiling, add the rigatoni pasta and cook according to package instructions until al dente. Drain and set aside, reserving a cup of pasta water for later.
In a large skillet, heat the olive oil over medium heat. Add the ground Italian sausage, breaking it up with your spoon as it cooks. Sauté for about 5-7 minutes until the sausage is browned and cooked through.
Once the sausage is nicely browned, add the diced onion and minced garlic to the skillet. Cook for an additional 3-4 minutes until the onion is translucent and fragrant.
Stir in the grape tomatoes and zucchini, cooking for another 5 minutes until the tomatoes start to burst and release their juices.
Pour in the chicken broth and crushed tomatoes. Add the lemon juice, Italian seasoning, dried oregano, salt, pepper, and red chili flakes. If you prefer a hint of sweetness to balance the acidity, sprinkle in a pinch of sugar. Stir everything together and let it simmer for about 10 minutes.
Add the cooked rigatoni to the skillet, tossing to combine with the sauce. If the mixture seems too thick, add a bit of the reserved pasta water to reach your desired consistency.
Sprinkle half of the grated parmesan cheese over the pasta and toss to combine. Remove the skillet from heat and garnish with fresh basil and the remaining parmesan cheese.
Serve hot, and don’t forget to offer extra parmesan on the side for those who want a little more cheesy goodness!