Thinly slice each potato about 3/4 of the way through. Tuck in thin slices of cold butter into slits. Spray potatoes with olive oil spray and season with salt and pepper.
Roast potatoes for 45 minutes. Remove and let cool for 5 minutes.
Cook bacon in oven until crisp.
Meanwhile, place cheese in slits and on top of potatoes and bake for 15 minutes more.
Remove and cover potatoes to keep hot.
Chop bacon into bits, and add to tops of potatoes.