1 Rinse the kale and cut the leaves from the stems. Remove the cabbage leaves from the head, cut out the thick veins and rinse. Cut the kale and the cabbage into equal strips and blanch for 15 minutes in boiling salted water. Remove, shock in cold water and drain.
2 Peel the onion and cut into fine dice. Heat the butter in a pan and sauté the onion until translucent, about 1 minute. Add cream and simmer. Season with salt, pepper and nutmeg. Beat the sauce with a mixer until frothy. Put the vegetables in the sauce, reheat and serve with freshly grated horseradish.