Instructions

1. Peel the celeriac and potato, then dice. Put them in a pan of lightly salted cold water and bring to the boil.
2. Simmer for 15-20 minutes until the vegetables are tender. Drain then put them back in the pan. Add the milk and butter. Using a potato masher, mash until you get a textured, creamy mixture. Add a couple of shaving of nutmeg and season with salt and pepper. Put the lid on and keep warm.
3. Meanwhile, peel the onion and slice it into very thin rings. Heat the oil in a frying pan and gently cook the onion for about 8 minutes.
4. When the onion is golden and starts to caramelise - turn the heat off and add to the celeriac mash. Crumble the cheese over and gently combine.
5. Serve warm.