01 -
Bring a large pot of salted water to a boil over medium-high heat.
02 -
Heat olive oil in a large, wide pot over medium heat. Add the onion and red pepper flakes, sautéing until the onion is very soft, about 10 minutes.
03 -
Add Italian sausage, breaking it into small pieces with a wooden spoon. Cook until browned with no pink remaining.
04 -
Stir in the minced garlic and cook for 1 minute until fragrant. Add tomato paste and cook briefly, stirring to combine.
05 -
Add grape tomatoes, white wine or chicken broth, salt, and black pepper. Cook for about 10 minutes, stirring occasionally, until the tomatoes burst and release juices. Gently press tomatoes with a wooden spoon if needed. Stir in diced zucchini and cook for 5 minutes.
06 -
Add rigatoni to the boiling water and cook for 9 to 10 minutes until al dente. Reserve 120 ml of pasta water, then drain.
07 -
Toss the drained rigatoni directly into the sauce pot. Add reserved pasta water a little at a time if the sauce needs loosening.
08 -
Stir in chopped fresh basil. Divide among bowls and top with freshly grated Parmesan cheese.