Boil the pumpkin and potatoes in water to cover, until soft.
Meanwhile, chop onion finely and fry in oil; chop garlic and add to the onion; chop chilies into rings and add to onion.
Saute all until onions are translucent then add to the pumpkin and potatoes. Add all the vegetables and cooking water to the blender and blend until smooth. (This may take a couple of goes). Return the blended soup to the saucepan and heat until bubbling.
Add the cream and grated cheese and stir through until cheese is melted. Add pepper and salt to taste.