Heat the oil in a 4-quart saucepot over medium heat. Add the onions, carrots and ginger and cook until they're tender-crisp. Add the red pepper and cook for 1 minute.

Stir the broth and sweet potatoes in the saucepot. Heat to a boil. Reduce the heat to low. Cover and cook for 20 minutes or until the vegetables are tender. Stir in the peanut butter.

Place 1/3 of the broth mixture in a blender or food processor. Cover and blend until smooth. Pour into a large bowl. Repeat the blending process twice more with the remaining broth mixture. Return all of the pureed mixture to the saucepot. Cook over medium heat until the mixture is hot. Season to taste. Divide the soup among 8 serving bowls. Top each serving of soup with the green onions and peanuts.