Cut the pumpkin flesh and onion into small pieces. Melt the butter and sweat the onion in it. Add the pumpkin and steam. Then dust with flour, stir and pour the beef broth and cream on top. Cook everything until the pumpkin is passable. Then puree in a blender or hand blender. Stir in the spices and crème fraîche. When serving, drip some pumpkin seed oil on it or sprinkle with pumpkin seeds, depending on your taste.