Watercress and mussel risotto

Pour the stock into a large saucepan and bring to the boil, then turn down to a very gentle simmer. Cover and keep warm

Blanch about 260g of the watercress in boiling salted water for two minutes, then refresh in ice water. Reserve the other 40g for garnish

Once the watercress has cooled, blend it with 50ml of the hot stock until you have a smooth purée. Reserve for later

Place a large saucepan over a high heat. Add the mussels and the white wine, which will boil vigorously as soon as you pour it in – make sure you get the lid on the pan straight after. Cook the mussels for five minutes, then remove from the heat and drain. Reserve the mussels in a bowl, strain the stock through a fine sieve and keep both for later (discarding any mussels that haven't opened)

To make the risotto, melt the butter into the olive oil in a pan over a low heat. Sweat the onion and celery with a good pinch of salt until soft and translucent

Turn the heat up to medium, add the garlic and thyme and cook for another minute, then add the risotto rice and fry for a minute or two, making sure all the grains are coated in the butter and oil

Deglaze the pan with a splash of the reserved liquor from the mussels and reduce by about two-thirds

Now start adding the hot stock, a ladle at a time. Stir each ladle of stock into the risotto gently – you want the pan to be steaming and very slightly bubbling, so the rice cooks but you have plenty of time to stir and release the starches in the rice. Once the stock has been absorbed, add another ladle and repeat

Once you’ve used most of the stock, check the rice. It’s ready when it’s al dente – cooked, but with a very slight bite in the middle of the grain. Once the rice is cooked, take it off the heat and stir through the watercress purée, adding some of the reserved mussel liquor to help loosen the risotto further. Check for seasoning and add some extra salt if needed

To serve, plate a ladle of the risotto and garnish with a few mussels, a squeeze of lemon and a few sprigs of watercress