In a large saucepan, saute onion and carrot in butter for 4 minutes or until crisp-tender. Stir in the broth, chicken, cauliflower, beans and macaroni. Bring to a boil. , Reduce heat; cover and simmer for 15-20 minutes or until macaroni and vegetables are tender. Add spinach and pepper; cook and stir until spinach is wilted. Garnish with croutons if desired.