A wonderful way to use up leftover mashed potato to make a comforting winter’s lunch, I like to use cavolo nero here for its robust flavour and springy texture. Mature Comté goes really well.
Cut out the central rib of each leaf of cavolo nero and discard, then cut the leaves into wide strips. Melt 30g of the butter in a saucepan and add the cavolo nero, a splash of water and season with salt and black pepper. Turn heat up high and stir the cavolo nero to coat it in the butter, water and seasoning, then turn the heat down to medium, cover the pan and cook for about 3 minutes, until it is wilted, giving the pan a shake every now and then. Drain off any excess liquid.
Heat the remaining 30g butter and about ½ tablespoon oil in a large non-stick frying pan over a high heat, then tip in the potato and spring onion and fry. As it cooks, you want it to brown and char slightly – make sure to spread it out over the base of the pan and keep breaking it up and scraping the bottom of the pan so that the lovely, crunchy brown bits are mixed in.
Mix in the cavolo nero and then the Comté and turn the heat down to medium. When the Comté starts to melt, stop turning the mixture over – just press it down every now to flatten the surface and cook over a low heat until it is golden brown on the bottom.
Meanwhile, in a separate frying pan, heat ½ tablespoon of oil and fry the eggs over a medium heat so that the whites are set but the yolks are still runny – season each egg with a little salt and black pepper as they are cooking. Place the four fried eggs on top of the bubble & squeak and serve in the frying pan for everyone to help themselves.