Melt butter in a large saucepan.

Add onions and cook for about 5 minutes, until soft.

Add the squash, potatoes, and paprika and bring to a boil.

Lower the hear to low, cover, and simmer for about 35 minutes until all the vegetables are soft.

Pour soup into a food processor or blender and process until smooth.

Return soup to pan and stir in cream (if using).

Season with salt and pepper and reheat slowly.

Stir in chopped chives just before serving.