Grease the inside of the crockpot with the butter liberally.
Place the prepared potatoes inside of the crockpot, then pour the broth over them.
Cook on low for 6-8 hours or on high for 3-4 hours. If you can, stir them once or twice.
When the potatoes are ready and YOU are ready, mash them with a potato masher OR a hand mixer on low speed. Do not beat the potatoes on a high speed, they will get gummy. A hand mixer on the lowest speed does an excellent job.
Add in enough milk to make them creamy if needed, then place into your casserole of choice.
Nutrition is an automatic estimate and will vary with the brands you use.
Recipe from https://fastandslowcooking.com/slow-cooker-mashed-potatoes/