Using a mortar and pestle, crush the fennel seeds.
Heat the olive oil in a large heavy-based stockpot over medium heat. Cook the onion, carrot and celery, stirring, until the onion is soft (approximately 4 minutes).
To make the Italian sausage ragù, break up the sausage meat with your hands and add it to the stockpot. Add the thyme and cook, stirring with a wooden spoon, breaking up any lumps until the sausage meat is lightly browned all over. Add the red wine and cook for about 5 minutes or until the wine has reduced. Add Italian passata and bring to the boil. Reduce heat to low, then simmer for a further 1 hour. Add water to the ragù, as needed to keep the sauce lovely and moist.
Meanwhile place a large pot with water on high heat and bring to the boil. Add a pinch of salt and rigatoni pasta to the boiling water and cook until ‘al dente’ – refer to the cooking time specified in pasta packet instructions. Drain the pasta.
Add pasta to the stockpot with Italian sausage ragù and toss to combine, then remove from the heat. Divide among deep serving bowls and serve with grated Parmigiano Reggiano on top – Buon appetito.