Sweet potato, celeriac and bacon soup

Cut the bacon into strips then dry fry in a large saucepan until brown and crispy. Remove and set aside for the garnish. Add the extra virgin olive oil to the pan, add the sweet potato and celeriac and sauté for 2-3 minutes. Add the stock and bring to the boil then simmer for 10-12 minutes, or until the vegetables are nearly cooked. Stir in half the crème fraîche and courgette, bring to the boil. Add the herbs and simmer for 2 minutes. Blend to a smooth puree. Season to taste, adding a little more water if the soup is too thick. Pour into individual soup bowls and top with frazzled bacon, a spoonful of the remaining crème fraiche and some chives. Serve with slices of ciabatta bread.