Remove and discard the outer leaves of the cabbage and cut into wedges. Cut away the core and shred the leaves as finely as possible. Melt butter in a large pan until sizzling, add the star anise and cinnamon and sizzle for a few minutes. Tip in the onion, beetroot and cabbage and sprinkle over the sugar. Then pour in the vinegar and orange juice, season generously and stir well. Cover the pan and cook over a low heat for 45 mins, stirring occasionally.
Stir in the apples with the cabbage and cook for a further 35 – 45 mins until the cabbage is soft.(the cabbage may be cooked up to this point and chilled for 2 days or frozen for up to 2 months). Stir in half the horseradish and transfer to a serving dish. Mix the remaining horseradish with the parsley and orange zest and scatter the mixture over the dish before serving.