1Mix cauliflowerets, tomatoes and onion in 3 1/2- to 4-quart slow cooker. Mix remaining ingredients except spinach; pour over vegetables.
2Cover and cook on low heat setting 4 to 6 hours or until cauliflowerets are tender.
3Stir in spinach leaves. Cover and cook on low heat setting 10 to 15 minutes or until spinach is tender. Spoon into small bowls to serve.