Creamy Bubble and Squeak Soup with Crunchy Bacon

Bubble and squeak is reputed to have got its name because it echoes the sound the ingredients make when frying. Usually thought of as a nineteenth-century dish of potato and cabbage leftovers, the dish was originally made with beef and cabbage, without potato. Here, I have taken the potatoes and mixed them with onions and Brussels sprouts, the alternative to cabbage. This version has been blitzed to a smooth, creamy-soft finish, but it can, if preferred, be left in its rustic, brothy consis