For the cheese soup, first chop the cheese. Peel and finely chop or squeeze the garlic.
Make a roux in a pot. To do this, heat the butter and stir in the flour. Deglaze with the white wine and add 1 liter of water. Add the garlic and soup seasoning. Then stir in the cheese until it is completely melted. Season to taste with salt, pepper and nutmeg.
Mix egg yolk with crème fraîche and stir into cheese soup just before serving.