In a large pan, fry the onions in oil until translucent and soft. Add squash and carrots and stir, cooking for a further 5 minutes. Add thyme and season well with salt and freshly ground black pepper. Pour over stock and bring to boil. Allow to simmer gently for 30 minutes, or until vegetables are cooked through.
Remove from heat and allow to cool slightly. Using a hand blender or a liquidiser, blend to a smooth soup. If too thick, add a little more stock until desired consistency is achieved.
Divide soup into bowls and serve with a dollop of crème fraiche and parsley.
Notes
For a fiery kick, add a diced chilli. Remember, the smaller the chilli, the hotter the taste. Fry with onions in step 1.