For the Fish, brush slices of sourdough bread lightly with egg white. Place squares of blue eye onto the slices of bread and cut the bread to the same size as the fish square. Repeat this process for remaining pieces of fish then transfer squares, bread side down, onto a paper-lined tray. Place a second layer of baking paper on top of the fish squares and top with a second baking tray to slightly weigh down. Set aside in the fridge for at least 10 minutes or until required.
For the Mushroom Sauce, heat oil in a medium frypan over medium heat. Add shallots, garlic and thyme and sweat off until softened, about 1 minute. Transfer to a large saucepan over low heat. Reserve frypan back on the heat and add 1 tablespoon of oil. Add mushrooms and cook until caramelised, about 2 minutes. Add kombu, bonito, vermouth and wine and simmer for a further minute. Transfer to the reserved large saucepan with the shallots. Add chicken stock and bring to the boil over high heat. Once boiling, reduce heat to low and simmer for 45 minutes. Strain through a fine sieve into a clean bowl and set aside until required.
For the Mushrooms, heat oil in a medium sized fry pan over medium heat. Add crushed garlic and sauté until soft. Add mushrooms, thyme and butter and continue to fry, stirring continuously, until caramelised. Season well with salt and freshly ground white pepper then set aside, keeping warm.
For the Celeriac Puree, place all ingredients into a saucepan over low heat, ensuring celeriac is completely covered with liquid. Simmer until celeriac is soft, about 20-25 minutes. Remove from heat and transfer to a food processor and blend until smooth. Pass through a fine sieve and season to taste. Transfer to a piping bag and set aside.
For the Ramps, heat oil in a small fry pan over medium heat. Add ramps and sauté until just soft, about 30-45 seconds. Remove from heat and set aside.
To cook the Fish, drizzle some olive oil into a medium sized fry pan and place a piece of baking paper into the pan to prevent fish from sticking. Drizzle a little more olive oil on top of the baking paper and place onto medium heat. Remove fish pieces from the fridge and add to the pan, bread side down. Allow to crisp for about 1 minute, then reduce heat and continue cooking until fish is almost cooked through. Flip fish over and add 1 tablespoon of butter to the pan and continue to cook until fish is just cooked through. Season well, remove from heat and set aside to rest.
To finish the Mushroom Sauce, measure out 500ml of the reserved mushroom stock into a clean saucepan and place over medium heat until slightly thickened. Add whipped cream and stir through until combined. Season to taste and set aside, keeping warm.
To serve, arrange some Ramps on the plate and top with two pieces of the Fish. Pipe some Celeriac Puree onto the plate and place some of the Mushrooms on top of the fish pieces. Finish with a drizzle of Mushroom Sauce and garnish with nasturtium leaves.