Boil the whole potatoes with the skin and, when tender, drain and peel. Reduce to a puree the potatoes still warm with the help of a potato masher and work with flour, a little at a time, the egg yolk and a pinch of salt. Quickly knead the mixture, form strands about 2 cm thick and then cut the last pieces in order to obtain the gnocchi. Try to complete everything when the dough is still lukewarm.
Spread the gnocchi on a baking sheet covered with oven paper and freeze them with the function of shock freezing of Freddy.
Remove any soil from the mushrooms, wash them quickly under running water, dry and chop coarsely to the knife. Heat a little olive oil in a pan with a clove of garlic and cook the mushrooms seasoning with salt, pepper and some fresh thyme leaves.
Boil plenty of salted water in a large pan and cook the gnocchi directly from frozen food until they float.
Drain and chop a couple of minutes with mushrooms. Serve with grated Parmesan cheese.