To make onion powder, roast the onions in 150C oven for 2 hours or until it crumbles to the touch. Allow to cool and blitz in a food processor to dust. Store in an airtight container until needed.

First cure the fish. Mix the salt, sugar, orange and lemon zests. Pile on to the fish and rub all over. Leave in the fridge to cure for 30 minutes. After this time remove from the fridge, wash off the excess and pat dry.

Now make the beurre noisette. Put the butter and seeds from the vanilla in a pan and melt on a medium heat. Cook, swirling the pan until it is nut brown. Remove from the heat and allow to cool to room temperature.

Preheat your water bath to 52C. Put the fish and half the beurre noisette into a vacuum bag and seal. Sous vide for 20 minutes, drain and serve.

For the escabeche, preheat the water bath to 80C. Finely slice the carrot, onion, garlic, and fennel. Pop into a vacuum bag along with the liquids and coriander seeds and massage well to mix. Seal and cook for 20 minutes. To finish, pour the bag into a warm pan and mix through the freshly chopped coriander. Check seasoning before serving.

For the celeriac, peel and dice into large cubes. Preheat the water bath to 80C. Add to a vacuum bag with the remaining beurre noisette. Seal and cook for 45 minutes. Drain and serve, topping with burnt onion powder.