Roast beef & caramelised onion toasties

Method

• step 1

  Slowly cook the onions in the butter and oil in a heavy-based saucepan over a medium-low heat for 25-30 mins, or until soft, deeply golden and reduced by well over half. Remove from the heat, season with salt and set aside.

• step 2

  For the toastie, heat the gravy in a saucepan over a low heat. Add the leftover roast beef slices and warm through until piping hot, about 3 mins. Meanwhile, spread the bread slices with the mustard, then top two of the slices with the caramelised onions, the cheeses and roast beef, reserving the leftover gravy. Sandwich with the remaining two bread slices.

• step 3

  Spread the butter over the outside of the sandwiches, then heat the sunflower oil in a frying pan over a medium heat. Fry the sandwiches for about 5 mins, turning over halfway through and pressing down using a pan lid or spatula until deeply golden with melted cheese. Remove from the heat, cut the sandwiches in half and serve with the reserved gravy for dunking.