Peel the potatoes and celeriac and cut into cubes. Cook in boiling salted water until soft for about 20 minutes. Drain, add butter, half of the cream and half of the milk and mash. Keep adding the cream and milk until the puree has the desired consistency.
Crush the peppercorns, allspice and cloves in a mortar and add with the grated nutmeg. Add a dash of soy sauce, a dash of walnut vinegar (if you don`t have one, use cucumber water) and the parsley and mix everything together. Season with salt, serve and sprinkle with the parmesan.