Sweet Potato & Pear Soup

Melt the butter in a large pot over a medium heat, and sauté onion for 2-3 minutes until softened but not brown. Add the diced sweet potato and diced pear, and sauté for 3-4 minutes. If using canned pears, only sauté the diced sweet potato at this stage and add the pears later. Add the chicken broth to the pot, bring to the boil and simmer gently for 20-25 minutes, or until the sweet potato (and pears) are soft. If including wine in your soup, add this in the last 10 minutes while the soup is simmering. Cool the soup for about 30 minutes. If using canned pears, drain these well, reserve the juice and add the pears now. They will help to cool down the soup. There is no need to chop the pears as the soup is about to be processed. In batches, process the chicken broth, sweet potatoes and pears until smooth in a blender or a food processor. Adjust the thickness of the soup so that it is to your liking by adding either more pears or some of the reserved pear juice, or more wine. Return the soup to the pot. If serving straight away: gently reheat, without bringing to the boil, stir in a swirl of yogurt and garnish with fresh mint or parsley. If serving later: refrigerate after processing. If taking to work for lunch: take the required quantity of yogurt in a separate container and spoon onto soup after it has been heated in the microwave. If freezing: freeze after processing. When ready to serve, defrost, gently reheat, without bringing to the boil, stir in a swirl of yogurt and garnish with fresh mint or parsley.