Thinly slice the red cabbage and place it in a heavy-based pot.
Add the sliced red onion, sliced apple, sultanas, balsamic vinegar, muscovado sugar, olive oil and mixed spice.
Season generously with salt and pepper, then mix everything together well.
Cover the pot with a lid and cook over low heat, stirring occasionally, for about 45 minutes, until the cabbage is soft, tender and glossy.
Taste and adjust seasoning if needed.
Serve hot, or prepare ahead and reheat when needed.
Garnish with chopped parsley or basil if desired.