An easy sweet potato soup can be made by pureeing cooked sweet potatoes with ginger, cinnamon and nutmeg. These ingredients are then mixed with milk, seasoned and simmered in a soup pan.
To make sweet potato soup, cook 1 tablespoon of flour and 1 tablespoon of salted butter in a sauce pot over medium heat. Stir constantly until the mixture takes on a light caramel color. Then add 1 1/2 cups of chicken or vegetable broth and 1 tablespoon of light brown sugar. Bring this to a boil, then lower the heat to reach a simmer. Stir in 1 1/2 cups of cooked sweet potatoes, 1/4 teaspoon of ground ginger, 1/8 teaspoon of cinnamon and 1/8 teaspoon of ground nutmeg. Bring the mixture back to a simmer, and cook for five more minutes.
Use a blender to puree the soup in batches before returning it to the pot. Add 1 cup of milk and reheat slowly. Season the soup with salt and pepper before serving in warm bowls. This recipe comes out fairly thick, and can be thinned using water, cream or broth. A dollop of sour cream on top of each serving can be a nice counterbalance to the sweetness of the soup.