Line crockpot with foil, leaving enough to cover the potatoes when finished - this will help to not stick and to steam the potatoes.Layer half each of the bacon, onions, potatoes and cheese in crockpot. Season to taste with salt and pepper and dot with (real) butter.Repeat layers of bacon, onions, potatoes and cheese. Dot with butter.Cover with remaining foil.Cover and cook on low for 4-6 hours.