Cut the potatoes and place in crock pot. Add about a 1/4 cup water at the bottom. On top of the potatoes, place your cubed butter. Cook on low for 5-6 hours or on low for 2-5 hours
Once done, add your yogurt, milk and salt/pepper. If you’re going to use your electric mixer, barely mix until mashed up. You don’t want to over beat your potatoes or they can turn into a paste (still good, but not as good as fluffy potatoes).