1. Combine the cheese, butter, flour, mustard and Worcestershire sauce in a saucepan and mix together.
  2. Add the stout and stir over a gentle heat until melted and forming a thick paste. Leave to cool.
  3. Toast the bread and spread the cheese mix over.
  4. Place under a hot grill and cook until bubbling and golden.
  5. Serve with slices of apple or a tomato and rocket salad.