Over-the-Rainbow Minestrone

Cut stems from chard; chop stems and leaves separately. Reserve leaves for adding later. In a large skillet, heat oil over medium heat. Add onion and chard stems; cook and stir 3-5 minutes or until tender. Transfer to a 6-qt. slow cooker., Stir in broth, tomatoes, kidney beans, garbanzo beans, squash, pepper, carrot and garlic. Cook, covered, on low 6-8 hours, until vegetables are tender., Stir in pasta and reserved chard leaves. Cook, covered, on low 20-25 minutes longer, until pasta is tender; stir in pesto. If desired, serve with additional pesto, Parmesan cheese, red pepper flakes and fresh basil.