Add all the ingredients, except the dippers, to small slow cooker.
Cook on low for 3 to 4 hours. If you use fresh, chopped spinach, you could cook on high for 2 hours. The frozen spinach needs at least 3 hours to warm up and incorporate into the sauce.
Keep warm until serving. If desired, transfer to serving dish, or keep warm and serve from the slow cooker.
Use chips, chunks of bread, pita chips, crackers or other "dippers" with this delicious dip. Enjoy!