This bright red soup is popular around Eastern Europe, and is an excellent way to use up beets of any kind. This version uses tinned tomatoes but you can also make it with shredded red cabbage and grated carrot, depending on what you have to use up. You can also swap the butter for vegetable oil, and use unsweetened dairy-free yoghurt to make a vegan version.
Adapted by Chelsea from A Soup for Every Day, New Covent Garden Food Co.
Serves 4