Add, if you wish, a few chopped walnuts and a drizzle of oil. If you prefer, add some mustard mayonnaise with a little truffle oil – it will give a very distinctive touch to your bread roll. If you don’t like hot sandwiches you can eat it cold, just as it is before putting it in the oven. However, bear in mind that the heat tends to soften the cheese and to enhance the flavours, so this sandwich is much better warmed.