Pumpkin, Sweet Potato, Leek, and Coconut Milk Soup

vegetable oil

medium onion, finely chopped

small leek, finely chopped white part only (finely chopped - 1 small)

pumpkin, or Butternut Squash, peeled and cut into 2 cm cubes

large sweet potato, peeled and cut into 2 cm cubes ((about 3/4 pound))

vegetable stock

light coconut milk ((270 ml))

fresh cilantro leaves, chopped

more cilantro to garnish

salt, pepper, cayenne