Thinly slice the onion and apples and shred the cabbage as finely as possible. The use of a mandolin is strongly recommended here.
In an oven safe dish (mine was about 7" x 7") add about 1/3 of the shredded cabbage, followed by ½ the onion and ½ the apples.
Continue layering by adding another 1/3 of the cabbage, the rest of the onions, the rest of the apple slices and finally, the rest of the cabbage. Set aside.
Place your chicken breasts on top of the cabbage and add another sprig of rosemary, if desired.
In a small mixing bowl, add apple juice, apple cidar vinegar, Dijon mustard, rosemary, salt and pepper and mix until well combined. Pour over chicken and cabbage mixture.
Cover with aluminum foil and cook in the oven for about an hour, until chicken is cooked through.
Remove the chicken breasts and slice them on a diagonal
Divide cabbage/apple mixture between 2 serving plates and place sliced chicken breasts on top.