With the holidays over and our bellies still full from all those roasts, our appetites are turning towards simple, nourishing meals to keep us warm through winter. The ultimate example of course is soup. Soup is the last stop of the nose-to-tail gastronomic train — bones from heritage breeds make the best stock in the business. Carlo Petrini, the founder of Slow Food, proclaimed the best way to judge a restaurant is to try the soup – there is almost no margin of error when it comes to soup. One can’t dupe on the soup.