Half an Onion, butter, Butternut squash, rosemary, chicken stock.
Melt the butter in a large sauce pan. Fry the onion in the butter until soft. Add the chopped butternut squash (ensure you have removed all of the skin) and fry until soft. Add the rosemary and leave it to fry for a while.
Add the chicken stock and mix together well. When the butternut squash is soft, use a blender to liquidise the soup. Cook again for about 5 min.