Sort the chard, wash it well and weigh it finely (cut into very fine strips). Put aside. Finely dice the onion and sauté in a large pan with the butter. Add a little salt and the crushed garlic clove. Now add the chard with a little milk to the pan, mix everything well and cover and let simmer briefly. Finally, carefully thicken everything with a little sauce thickener (please do not put the sauce thickener directly on the chard leaves, but rather in the resulting liquid!) And season with salt and nutmeg.