Sweet Potato and Coconut Soup

1 tbsp. olive oil
1 lb. sweet potatoes, peeled and chopped into chunks
1 red onion, chopped
1 tbsp. Thai red curry paste
2 cups vegetable stock
2 cups coconut milk

Put the oil in a heavy-based saucepan over medium heat.  Add the sweet potatoes and onion, partially covered with a lid, and cook for 15 minutes, stirring often, until they are soft and just starting to turn golden.  Increase the heat to high, add the curry paste, and stir-fry for 3-4 minutes so that the paste cooks and becomes fragrant.  Add the stock and coconut milk and bring to a boil.  Transfer the mixture to a food processor (or use a blender stick) and whir until smooth.

OPTIONAL ADD-INSchilis
1 tsp. curry powder
hot sauce