Sea bass mariniere with fennel, British shellfish and sauce Normande

Begin with some prep, as this can all be done a good few hours in advance. If your scallops are still in their shells, open them up and remove the skirt and roe. Give the scallops a wash in cold water, then place in the fridge to firm up

Use a Parisienne scoop to cut out small balls of the courgette and carrot (if you don't have a scoop you can just dice them, but they look much prettier when spherical!) and set aside. Trim the tops off the fennel and slice into wedges, reserving the tops and peeling off the outer layer to cook with the prawns later. Set both the trimmings and wedges aside

If you're working with a whole sea bass, now is the time to fillet it and cut out 6 portions (if you've bought ready-portioned fillets, you can obviously skip this step). Check the portions over and remove any pinbones, then score the skin a few times to help the fillets stay flat when they cook. Reserve in the fridge

To make the mussel sauce, place a medium-sized pan over a medium-high heat and add a splash of vegetable oil. Add the shallots, garlic, thyme, peppercorns and star anise. Add a pinch of salt and cook until soft with no colour, around 3-5 minutes

Add the wine and Noilly prat and turn up the heat to full. Vigorously simmer for a few minutes to reduce slightly and cook off the alcohol, then add the mussels, toss well and cover with a tight-fitting lid. Cook on high heat for 2 minutes, until all the mussels open up

Strain the mussels through a colander set over a bowl to collect the juices. Set the mussels aside, discarding any that haven't opened. Pour the reserved liquid through a fine sieve into a small pan to remove any grit. Separate 75ml of the liquid and reserve to warm through the shellfish in later. Simmer the remaining liquid until reduced by roughly half

Meanwhile, cook the prawns. Place the carrot, lemon, onion, thyme and reserved fennel trimmings in a saucepan and cover with water. Add a pinch of salt, bring to the boil, then drop in the prawns. Turn off the heat and leave the prawns to cook in the residual heat for 3 minutes, then drain

Once the prawns are cool enough to handle, peel them (be sure to reserve the heads and shells in the freezer for making stock or bisque for another dish). Chop each peeled prawn tail into 3 pieces, removing the digestive tract as you do so, then add them to the 75ml of reserved mussel liquor and store in the fridge

Once the mussel liquor has reduced by half, add the double cream, bring it back to the boil, simmer for 1 minute, then add a knob of butter and whisk to emulsify. Set aside to reheat later

Pick the mussels from their shells and reserve 18 of the nicest looking shells to garnish the dish. Add both the mussels and the reserved shells to the prawns and reserved mussel liquor in the fridge, along with the brown shrimp, ready to gently reheat before serving

To cook the fennel, heat some oil in a pan over a medium-high heat and add the fennel wedges cut-side down. Add a pinch of salt and cook until dark brown and nicely caramelised. Turn the fennel over then add the thyme and garlic

Turn up the heat and add in the orange juice and butter. Bring to a rapid boil so the butter melts and creates an emulsion, then turn down to a simmer, season with salt and cover with a piece of baking paper (known as a cartouche). Simmer for 6 minutes until the fennel is tender, then leave in the pan ready to reheat

Next, finish preparing the vegetables. Bring a small pan of salted water to the boil and add a knob of butter, then add the balls of carrot and courgette. Cook for 2 minutes, then keep warm or reheat before serving. Cut the truffle (if using) into thin matchsticks

Set up a metal or bamboo steamer over a pan of simmering water. Season the sea bass fillets, then place them on sheets of baking paper. Add them to the steamer and cook for around 5 minutes or until nearly cooked (it will finish cooking in the residual heat whilst resting). To test it, stick a cocktail stick into the centre and it should glide in with any resistance

While the bass cooks, place the pan of shrimps, prawns and mussels over a low heat and very gently warm through. Bring the sauce back to a simmer, whisking thoroughly, and gently reheat the carrot and courgette. Slice each scallop into 3 pieces. Once the bass is cooked, leave it to rest for a few minutes, then season it with salt and a squeeze of lemon

Place 2 pieces of fennel on the centre of each serving plate. Place 3 slices of scallops around the fennel and season with salt, then add 3 cleaned mussel shells to each plate, placing a mussel back inside each one

Spoon the prawns, carrots and courgette over and around the fennel. Season the sauce to taste with salt and lemon juice – at this point you can briefly blitz it with a hand blender to froth it up a little. Add the chopped chives

Place a fillet of bass skin-side up on top of the fennel on each dish, then spoon the sauce around it (any remaining sauce can be served on the side). Garnish with the truffle (if using) and oyster leaves