Peanuts are known as groundnuts in West Africa, where this zesty soup originated. It's quick (ready in about a half hour) and easy and makes a great light meal when paired with biscuits or bread.
Heat the oil in a large saucepan over medium heat. Add the onion and the carrot and sauté until tender, about 3 to 5 minutes.
Add the sweet potato and the water, then cover and simmer for 10 minutes or until the sweet potato is soft. Stir in the condensed soup, peanut butter, curry, and 1/8 to 1/4 teaspoon of cayenne pepper (depending on the level of spiciness your family prefers), then bring the mixture to a boil. Remove the pan from the heat and let cool for 10 minutes.
Puree the soup in a blender in 2 batches (or use a handheld immersion blender), then return it to the pan and reheat it. Ladle the soup into bowls and, if you like, top it with a dollop of sour cream and a few chopped peanuts. Serves 6.