1) Heat the oil in a 4-quart saucepan.

2) Add the carrots and onions and cook until they're tender-crisp, stirring occasionally.

3) Add the peppers and cook and stir for 1 minute.Stir the broth and beans into the saucepan and heat to a boil. Reduce the heat to low. Cook for 25 minutes.Mash the avocado with a fork in a small bowl. Stir in the sour cream, cilantro and lemon juice.Spoon one-third of the broth mixture into a blender. Cover and blend until the mixture is smooth.

4) Pour the mixture into a large bowl. Repeat twice more with the remaining broth mixture. Return the blended mixture to the saucepan. Cook over medium heat until the mixture is hot and bubbling. Divide the soup among 8 serving bowls. Top with the avocado mixture.