Spray Slow Cooker with Pam so the potatoes will not stick. Add the washed potatoes, minced garlic and the Chicken Broth.
Cook on Low for 6 hours. You can cook on high for about 3-4 hours, but watch the sides of the potatoes to make sure they don't burn.
30 minutes before the time is up add the butter, cream cheese and Parmesan cheese. Stir in slightly and re-cover for the remaining 30 minutes.
After that 30 minutes you can use a potato masher or an Immersion Blender to blend. Fold in the Pesto.