Heat the oven to 400F. Remove any bruised or damaged leaves, and cut the red cabbage into 4 x 2cm thick steaks, leaving the stalk on so they stay intact.
Brush both sides with oil, season and put on a baking paper-lined tray. Roast for 30-40 minutes until golden and a knife pierces the stalk easily. Turn the steaks over halfway through cooking, and, if they’re browning too much before they’re tender, cover with foil and keep cooking.
Toast the hazelnuts in a dry frying pan until golden and toasted. Tip out and leave to cool, then roughly chop. Tip into a bowl with the chilli, mint, lemon zest and juice, maple syrup and 3 tbsp oil. Season and drizzle over the steaks.