Ideal Slow Cooker Size; 6-QuartCut stems away from the chard leaves and chop stems and leaves separately. Reserve leaves for adding later.In a large skillet, heat oil over medium heat. Add the onion and chard stems. Cook, stirring often for 3-5 minutes or until tender. Transfer to a the slow cooker.Stir in the broth, tomatoes, beans, pepper, carrot and garlic.Cover and cook on low for 6-8 hours or until vegetables are tender.Stir in the pasta, zucchini and reserved chard leaves. Cook, covered, on low 20-25 minutes longer or until pasta is tender.Serve topped with pesto.