Twice Baked Potato's

My friend Katie introduced these potatoes to me several years ago.  It's a great way to change up potatoes as a side dish.  The flavor of the potatoes with the onion and cheese is so yummy!  

10 potatoes
1/2 of an onion, finely chopped
3 tablespoons butter
salt & pepper
milk
cheddar cheese
bacon, cooked and crumbled (optional)

Using a fork, poke holes into 10 potatoes.  Bake at 350º for 1 hour.  Cut off the tops of the potatoes, and scoop out the insides, making the potatoes into a canoe-like shape.  Put the insides of potatoes into a medium bowl.  Add the onion, butter, salt and pepper, and enough milk to make it creamy.  Mash the potatoes, mixing all the ingredients.  Put mashed potatoes back into the potato skins.  Top with cheddar cheese, and bake at 350º for about 15 minutes, or until cheese is melted.  Top with crumbled bacon.