Celeriac remoulade

First, make the mayonnaise. Combine the egg yolks, mustard and vinegar in a bowl and whisk to combine. Season and slowly add the oil, whisking until fully incorporated.
Peel one of the celeriac and shave on a mandolin, using the julienne attachment. Bind with the mayonnaise in a bowl, seasoning heavily with more mustard and lemon juice.

Grapes

Wrap one of the celeriac in tin foil and bake in the oven at 180c until a temperature probe reads 94c in the centre. (Approximately 2 hours) Remove from the oven and rest for at least 20 minutes before carving.

Baked celeriac

Wrap one of the celeriac in tin foil and bake in the oven at 180c until a temperature probe reads 94c in the centre. (Approximately 2 hours) Remove from the oven and rest for at least 20 minutes before carving.

Celeriac veloute

Finely dice the onion and celery. Sweat in a pan with a little butter over a medium heat. Peel and dice the remaining celeriac, add to the pan and sweat for a further 5 minutes, without colour. Add 300ml cream and simmer until tender.
Season, blend and pass through a fine chinois. Pour into a siphon and charge once. Hold in a warm place.

Truffle puree

Finely slice the chestnut mushrooms and sweat in a little butter over a low heat until most of the water is cooked out. Add any leftover truffle peelings, 100ml cream and cook for a further 5 minutes. Season, blend and pass through a fine chinois.
Place into a squeezy bottle and keep in a warm place.

Mushroom foam

Combine the vegetable stock and dried cepes and reduce by half. Add 200ml cream and reduce by half again. Season and strain through a fine chinois, holding in a warm place.

To serve

Carve the celeriac into 2cm cubes, season with fleur de sel and pepper.
In the bottom of a warm bowl, place a little of the celeriac remoulade. Cover generously with the celeriac veloute.

Scatter some of the dressed grapes over the top of the veloute.
Froth the mushroom foam using a hand blender and ladle over the top, ensuring the entire surface of the veloute is covered. Place the baked celeriac in the centre, add a small dot of the truffle puree and garnish with freshly shaved autumn truffles.