1. Boil the potatoes in plenty of salted water for 15 minutes, or until tender. Drain well and mash until smooth.
2. Meanwhile, steam the cabbage for 5 minutes, or until tender, then dice.
3. Combine the potatoes and cabbage with the mustard, spring onions (if using) and egg in a bowl. Mix well with a wooden spoon and leave to cool.
4. Shape the mixture into 8 cakes. Dust each cake with flour until well coated.
5. Heat 1 tbsp of oil in a heavy-based frying pan. Fry 4 of the cakes over a medium heat for 3-4 minutes on each side, until golden, then repeat with the remaining cakes.
Image courtesy: Camera Press