Start by adding half of the oil and the broken sausages into a large, non-stick frying pan. Fry over a high heat and leave for 3 minutes to brown. Stir and continue to fry, maximising browning as much as possible.
After 8 minutes, remove the sausage and set aside. Add the onion into the pan and reduce the heat to medium/low. Season with salt and pepper and fry for around 4 minutes.
During this time, add your rigatoni to heavily salted boiling water. Set your timer to the packet time minus 2 minutes. Steam the broccoli over the pasta pan for 4 - 5 minutes.
Once the onion is translucent, add the garlic and fennel seeds. Fry for 2 minutes over a low heat. Then add the creme fraiche and cook for a minute, then add two thirds of the sausage back into the pan (reserving some for the topping), half of the pecorino, white wine vinegar and the cornflour slurry (cornflour + water) into the pan and stir through. Season with pepper.
Cook for a minute to bring up to temperature, then slowly pour the stock into the pan, whilst continuously stirring. Then pour the drained, al dente pasta into the pan and stir through, reserving extra pasta water to use as necessary. Cook over a low heat until the sauce is coating the pasta nicely and is well incorporated.
Serve with steamed broccoli and top with the reserved browned sausage, a crack of black pepper and grated pecorino.