Curried Sweet Potato-Peanut Soup

1 tablespoon peanut oil1 large yellow onion, chopped1 clove garlic, chopped1 can (28 ounces) crushed tomatoes5 cups vegetable stock or water2 large sweet potatoes, peeled and cut into 1-inch chunks 3/4 cup creamy peanut butter1 tablespoon curry powder 1/4 teaspoon cayenneSalt 1/4 cup chopped dry-roasted peanutsHeat the oil in a large pot over medium heat. Add the onion and garlic, cover, and cook until softened, about 5 minutes.Add the tomatoes, stock and sweet potatoes. Bring to a boil, then reduce the heat to low and cook uncovered until the potatoes are soft, about 30 minutes.Stir in the peanut butter, curry powder, cayenne and salt to taste. Remove from the heat and allow to cool.Puree the mixture in a blender or food processor until smooth, or use an immersion blender to puree the soup right in the pot. Heat the soup over low heat until hot. Serve sprinkled with the chopped peanuts.Serves six.Nutrition values per serving: 424 calories, 25 g fat (4 g saturated), 39 g carbohydrates 9 g fiber, 15 g protein, 0 cholesterol, 702 mg sodium.