In a pot over medium heat, warm the oil. Add squash, apples, and onions and stir gently for 10 minutes. Add curry powder, cardamom, and cinnamon and cook, stirring gently, for several minutes longer. Add chicken stock and cider, bring the mixture to a simmer, and cook, partially covered, for 20 minutes, or until squash is soft.

Purée the mixture (in batches, if necessary) in a food processor or blender, then return to the pot. Cook over medium heat until mixture is reduced by about one-third. Add cream and season with salt and pepper.