Steamed turbot with crushed-nasturtium broth

Serves 4

For the turbot

— 100g salt

— 100g fresh seaweed such as sea lettuce, or 25g dried seaweed

— 1 turbot, skinned, boned

and filleted

For the mussel stock — 300ml white wine — 1kg mussels, beards removed, thoroughly washed and drained

For the sauce

— 100g banana shallots,

finely sliced

— 30ml olive oil

— 200g button mushrooms,

finely sliced

— juice of ½ lemon

— 75ml Noilly Prat vermouth — 250ml double cream — 15g nasturtium leaves and stems, plus extra leaves and flowers to garnish — 30g baby spinach

— 1 garlic clove, finely sliced

For the quick-pickled courgette

— 150g white-wine vinegar — 90g caster sugar

— 12g salt

— 2 small yellow courgettes

Bring two litres of water to a boil then whisk in the salt to dissolve. Add the seaweed, remove from the heat then chill.

Portion the turbot into 120g pieces. Place these in the brine for eight minutes then remove and drain on a clean J-cloth.

For the stock, bring the wine to a boil with 300ml water then add the mussels and cover with a lid. Cook for three minutes, until the mussels have opened (throw away any that haven’t).

Tip the mussels into a colander, saving the liquid, then strain this through a double layer of muslin and set aside. You can save the mussels for a separate dish, or serve them alongside the turbot if desired.

To make the sauce, sweat the shallot in the olive oil with a pinch of salt in a lidded pan, for 10 minutes, until softened.

Add the mushrooms, another pinch of salt and the lemon juice, stir through then cover with the lid again and cook for another 10 minutes.

Add the Noilly Prat, bring to a boil, then add 400ml of the mussel stock along with the double cream. Reduce the heat and simmer for five minutes, then strain the sauce through a sieve, pressing the mushrooms and shallots with the back of a spoon to extract all the sauce.

Transfer the sauce to a blender, add the nasturtium, spinach and garlic clove, and blend for 30 seconds. Check for seasoning.

For the pickled courgette, add 450ml water to a pan with the white-wine vinegar, sugar and salt. Bring to the boil then remove from the heat and chill.

Slice the courgettes into 1mm-thick rounds, using a mandolin if you have one. Add to the pickling liquor and leave for 10 minutes, then drain.

Steam the turbot pieces until just cooked – approximately eight minutes.

To serve, place courgette slices in each bowl, overlapping neatly, then top with turbot. Scatter over some nasturtium leaves and flowers, then pour the sauce on top.