½ celeriac (about 350g), halved, thinly sliced, then roughly chopped
2-3 large leaves cavolo nero or spring greens, stalks removed, shredded
90g cooked ham hock, shredded
1 tbsp wholegrain mustard
2 duck eggs
25g Gruyère, cut into small chunks (optional)
Heat the butter and oil in a wide frying pan. Add the onion and cook slowly for 15 mins or until turning golden. Stir in the garlic and thyme for 30 secs, then add the celeriac and some seasoning. Stir to make sure the celeriac is well coated in the buttery onions, then add a splash of water and cover the pan with a lid or piece of foil. Cook for 8-10 mins until the celeriac has softened and is caramelising in places.
Add the cavolo nero and ham, and stir well. Increase the heat to wilt the cavolo nero and crisp the ham in places. Add a splash more water if anything starts to stick to the pan. Dot around spoonfuls of mustard, then create two spaces to cook the eggs. Add a drizzle more oil to the gaps if the bottom of the pan looks dry, then crack in the eggs. Dot the cheese around the pan and cover with a lid or foil for 2-3 mins. By this time, the egg whites should be cooked and the yolks still runny. Season the eggs with a little black pepper and serve from the pan.