In a large bowl, heat the oil and add the chopped garlic and simmer for about five minutes.Then, add the chili, salt, tomato paste, sweet potato and peanut butter and stir briefly.Then pour in the stock and mix until the tomato paste and peanut butter dissolve nicely, then cover the pan to boiling and then reduce the heat and cook for another 10 minutes until the sweet potatoes soften.
Add everything in a blender, and blend until you get a smooth and creamy texture of the soup. Serve warm and sprinkle with chopped peanuts if desired.