Wash and shred cabbage, removing central core, ribs and outer leaves. Cook in bacon fat, in a covered saucepan, for 5 minutes. Add sliced apples and finely chopped onion and garlic, and bring to a boil with just enough water to cover. Cover, reduce heat, and simmer until tender but still crisp - about 15 minutes. Drain, reserving liquid.
Combine wine vinegar with flour and brown sugar, and stir in the reserved liquid. Cook, stirring, until thickened. Stir into cabbage; add grated orange rind, and season to taste with salt, freshly ground black pepper and nutmeg.