- Preheat the oven to 200ºC fan oven/220ºC/gas 7. Put the potatoes on a large baking tray and sprinkle over with oil. Season with salt and pepper and mix everything together. Place in the oven for 30-35 minutes.
- To make the relish, heat the oil in a saucepan and add the onions. Fry until they begin to soften. Add the tomatoes and fry for 1 minute. Add the rest of the ingredients and simmer very gently for 3-4 minutes. Take care not to burn the honey.
- Mix the beef, onions, mustard and salt and pepper in a bowl. Form into 8 round patties. Place the crumbled cheese on 4 of the patties and then top each one with another pattie. Form together into burgers.
- Heat the oil in a frying pan and fry the burgers on a medium heat. They should be browned on the outside and cooked through. Should take 8-10 minutes, but check one to make sure.
- Serve with bread buns, salad or mini roast potatoes.