Wash the potatoes thoroughly under cold water to remove any dirt or debris, peeling them if desired for a smoother texture.
Place the washed potatoes in the bottom of your slow cooker, ensuring they are evenly spread out for uniform cooking.
Sprinkle the entire packet of Lipton onion soup mix over the layer of potatoes, allowing the seasonings to penetrate each potato.
Pour one cup of beef or chicken broth over the potatoes and soup mix, ensuring that there is enough liquid to facilitate cooking.
Dot the top with small pieces of unsalted butter and season with salt and pepper according to your preference before covering with a lid.
Cook on low for 6-8 hours or high for 3-4 hours until the potatoes are fork-tender; check occasionally to ensure they do not overcook.
Once done, check for tenderness, garnish with fresh parsley if desired, and serve hot as a delightful side dish.