Preheat the oven to 180'C.
Trim and pin bone the fish. Heat a pan until hot. Season the fish with Maldon sea salt and cook flesh side down until the flesh is golden brown. Finish cooking in the oven for 3 minutes. When the fish is cooked peel away the skin and turn to serve the golden brown side up.
Slice the potatoes about 1cm thick. Crush the garlic cloves and pick the thyme leaves. Cook the potatoes in a pan with the olive oil, crushed garlic and sprigs of thyme. Transfer to the oven and cook until golden and tender.
Soak the gelatin in cold water. Blanch the peas in hot stock for 2 minutes then add the cream and gelatin and blend until smooth. Pass through a fine sieve, season and pour into the siphon. Charge with a gas canister and leave in the fridge.
Place the potatoes in the middle of the plate and place the fish on top. Dot the mousse around the plate with the siphon and garnish with the pea shoots and a drizzle of olive oil.
«If violet potatoes are not available, use a waxy type such as pink fur apple or ratte.»