For the blue cabbage, wash, slice or chop finely and divide between 2 unperforated cooking containers.
Peel and core the apples and cut into thin slices. Put the bay leaves with the cloves in the onion. Mix apples, onion, lard, red wine, balsamic vinegar and the currant jelly with the cabbage, season and cook (at 100°C for 120 minutes or at 120°C for 60 minutes).
Finally, fold in the grapes and season the blue cabbage to taste. If desired, thicken the blue cabbage with stirred flour (at 100°C for 3 minutes).