The French culinary term "demi-deuil," or "half-mourning," describes dishes containing both black and white ingredients. In classic cuisine, the "white food" (usually poultry, replaced here by a fish) is encrusted with slices of truffles.

1. Place slices of white truffle between the skin and flesh of the plaice (the black skin side with the bones) and steam cook at a low temperature using a sous-vide (vacuum) process.
2. Steam cook the spinach; blend until smooth with white truffle, butter and parmesan.
3. Combine with some hollandaise sauce that has been prepared separately.
4. Season with salt and a little lemon juice.
5. Arrange the plaice and the spinach on a plate and grate white truffle over top at the moment of serving.