Step 1

Heat the oil in a large frying pan. Squeeze the sausages from their skins into the pan and break up into small pieces. Cook over a medium-high heat for 8-10 mins until browned and crispy in places. Remove using a slotted spoon and set aside.

Step 2

Boil a full kettle. Add the leeks to the pan and season. Cook over a low heat for 10-12 mins until softened and just starting to caramelise. Meanwhile, fill a large pan with the boiled water and some salt, and cook the pasta following pack instructions. Drain, reserving 150ml of the cooking water.

Step 3

Add the garlic and fennel seeds to the leeks and cook for 2 mins. Stir through the mustard and sausages, then pour in 100ml of the pasta water and let it bubble for 1 min. Tip in the pasta, sprinkle over the lemon zest and toss everything together, adding a little more pasta water if needed. Divide between plates and top with Parmesan and black pepper before serving.