Sweet Potato Soup with Ginger, Leek and Apple

Heat the oil or butter in a heavy soup pot or Dutch oven over medium heat. Add the leek and cook, stirring, until it is tender, about 5 minutes. Add the ginger and stir together until fragrant, about 1 minute. Add the sweet potatoes, regular potato, apples and water and bring to a simmer. Add salt to taste, reduce the heat, cover and simmer 45 minutes to an hour, until all of the ingredients are thoroughly tender.

Using an immersion blender, purée the soup (or you can use a regular blender, working in batches and placing a kitchen towel over the top to avoid splashing) until very smooth. Return to the pot, heat through and adjust salt. Ladle into bowls, squeeze a little lime juice and sprinkle a little chili powder over each serving and serve.

Yield: 6 to 8 servings.