leeks

Heat a large, wide pot over medium heat. Add the olive oil, add the leeks with a small pinch of salt.
Cook gently for 6–8 minutes until soft and silky but not coloured.
Add the garlic and cook for a further 30 seconds.

sauce

Stir in the symplicity. nduja and cook for 1–2 minutes until it melts into the leeks and releases its smoky, paprika and chilli-rich oils.
Increase the heat slightly. Add the white wine and let it bubble for 1–2 minutes until reduced by roughly half.
Pour in the stock and bring to a simmer.

mussels

Add the mussels, cover with a lid and cook for 3–4 minutes, shaking the pan once or twice, until they have opened.
Discard any that remain closed.
Stir through the butter, lemon zest, parsley and a generous grind of black pepper. Taste and adjust seasoning if needed.
Serve immediately in warmed bowls with plenty of crusty bread to soak up the spiced butter broth.

barbecue version

Split and wash the leeks, brush lightly with olive oil and char them cut-side down over a hot grill until deeply caramelised and smoky, 4-5 minutes per side.
Chop roughly and set aside.
Place the mussels in a cast-iron pan or sturdy foil tray with oil, a spoonful or 2 of symplicity. nduja and a splash of white wine.
Sit directly over the grill, lid down, and cook for 4 - 5 minutes, shaking occasionally, until the shells open and the nduja melts into a smoky, chilli-butter sauce.
Stir the chopped charred leeks back through at the end and finish with lemon zest, butter and parsley before serving straight from the pan.