Bake potatoes in 350˚ oven for 60 minutes. While potatoes are baking cook bacon until crisp.
Cool potatoes about 10 minutes and slice in half. Carefully scoop out the inside of each half into a mixing bowl. Leave a small amount of potato on the skin.
To your bowl add butter and lightly mash. Add crumbled bacon, parmesan and ½ cup of cheddar. Lightly mix ingredients together. Spoon potato mixture back into the potato skins. (You may have some skins left over.) Top with remaining cheddar cheese. If you don't plan to bake right away, cover and refrigerate overnight.
Bake at 350˚ until cheese melts, about 20 minutes.