Cut the foie gras slices in half and season with fleur de sel, freshly ground black pepper and the white truffle oil.
Beat the eggs white with a little water to obtain an egg wash.
Place the foie gras pieces on to 12 of the ravioli sheets. Brush the egg wash on to the edges of the pasta and then seal the ravioli with a second sheet. Take care not to trap any air inside the ravioli and firmly press the edges together. Use a pastry cutter to trim the ravioli edges.
Peel the mushrooms and the shallots. Finely dice the shallots.
Cut 6 mushroom heads into small cubes and set aside for the garnish. Finely dice the 6 stalks and the rest of the mushrooms.
Heat a saucepan and add a drizzle of olive oil. Add the shallots to the pan, season with salt and cook for 3 minutes before adding the diced mushrooms. Cover with water and leave to cook for 15 minutes. Season with salt and pepper, add the cream and then mix in a food processor.
Crush the hazelnuts. Roughly chop the chervil. Squeeze the juice from the lemon.
Mix together the cubed mushrooms, the hazelnuts and the chervil. Season with salt, pepper, olive oil and the lemon juice.
Bring a large pan of salted water to the boil, reduce to a simmer and cook the ravioli for 3 minutes.
Place a spoonful of the marinated mushrooms in the bottom of your serving dish. Place 2 raviolis on top, add the mushroom veloute and finish with fresh parmesan shavings.
«Be careful not to overcook the ravioli - remove from the pan as soon as the pasta is translucent.»