Remove the bones from the cod steaks.
Wash the mussels.
Place the cockles in a bowl of cold water with a pinch of salt. Change the water regularly to ensure that all of the grit is expelled.
Peel and dice the shallots.
Heat two saucepans and add olive oil to each one. Spread the shallots between the two pans, add the herbs and sweat with a pinch of salt for 1 minute.
Add the mussels to one pan and the cockles to the other. Add white wine to each pan, cover and cook over a high heat for 5 minutes or until the shells have opened. Discard any shellfish that do not open.
Set aside 3 whole shellfish per person and remove the rest from their shells. Cover with cling film to prevent them from drying out.
Pass the cooking liquid through a sieve and then return to the pan. Bring to the boil and check the seasoning, adding salt and pepper if necessary. Add the cod to the pan skin-side down. Cover and cook for 6 to 7 minutes.
Remove the skin from the cod once cooked.
Add the cream to the liquid in the pan, cook over a medium heat until you have a smooth, glossy sauce.
Add the shellfish to the pan and warm through for 1 minute when ready to serve.
Peel the carrots and the sweet potatoes and then cut into 3mm thick slices.
Thinly slice the spring onions.
Add a knob of butter to a saucepan and then add the spring onions. Add a pinch of salt and the curry powder. Cook for 1 minute before adding the carrots and the sweet potato. Season with salt and then add the cream and the milk. Cover and cook for 20 minutes. Check the cooking of the vegetables using the tip of a knife. Transfer the vegetables to a food processor and start to blend to a purée. Add the cooking cream a little at a time until you have a smooth purée. Add a little water if necessary. Add the butter and season with salt and pepper.
Wash all of the herbs and gently pat dry.
Pick the chervil and the parsley leaves from their stalks.
Chop the chives into 2cm pieces.
Mix all of the herbs together and season with salt, pepper, olive oil and the vinegar.
Place a spoonful of carrot and sweet potato purée on each plate. Use the back of a spoon to spread the purée into a tear shape. Place the cod steak on top and then add the shelled mussels and cockles. Add three whole shellfish to each plate. Place a small handful of the herb salad on top of each piece of cod and finish with a drizzle of the shellfish sauce to serve.
«The cod can also be cooked in the oven: place in a baking dish, add the shellfish sauce and cover with foil. Cook for 7 minutes at 220°C.»