• Quarter the avocados. Remove the stones and peel and discard. Cut off a few thin slices of avocado and reserve them for garnish. Brush with a little of the lemon juice to prevent discoloration. Roughly chop the remaining avocado and mix it with the remaining lemon juice.
• Cook the onion, garlic and chilli in the butter or margarine until softened. Reduce the heat, add the flour, cook for 2 minutes stirring. Add the chicken stock and milk, stirring all the time. Bring to the boil, add the avocado and seasoning, then reduce the heat and simmer gently for 2 - 3 minutes. Blend in a liquidiser until smooth. Return the soup to the saucepan and over a very low heat stir in the soured cream.
• Pour the soup into individual soup bowls and garnish each serving with the reserved slices of avocado. Serve immediately.

Cook's Tip

• To ripen avocados quickly, place in a brown paper bag with a ripe banana or tomato.