Pre heat oven to 150 degrees. Combine the soy sauce, honey, lemon, garlic & ginger, add a little olive oil & submerge fillets into the marinade for around 10 minutes or longer.
Peel and cut your sweet potato into chunks, boil until tender.
In a high topped jug, add the egg yolk, sugar & mustard. Whisk together and after a minute slowly add (whilst still whisking) the rapeseed oil & then the double cream. Crumble the seaweed sheet in a bowl, tearing into little pieces & add this to the salad cream, whisk together & set aside in the fridge.
Put a little oil in the pan on a med-high heat. Add the fillets skin face down for around 1 minute, flip & cook the flesh for 30-45 seconds. Once both sides seem nice and brown, place them onto tin foil and close it in on the fillets to create little parcels. Pop in the oven for 8 minutes.
Once the potato is soft, drain water & begin mashing. Add the spring onion, a tsp of lazy chillis, salt & pepper.
Once fish is cooked through, plate the potato in the centre, lay the fillet on top & drizzle with the seaweed sauce. Enjoy!