Scoop out most of the inside, leaving enough to keep the skin from tearing.
Put the potatoes in a bowl and add butter or margarine, salt and pepper. Blend well with a fork mashing any lumps you may have.
Now put the blended potatoes back into the empty potato skins filling each one evenly.
Top with grated cheese;
And place in a baking dish. I have found that the potatoes tend to fall over so I use a pan with sides.
Bake for 20 minutes at 350-degrees until the edges are crisp.
I usually bake more potatoes than needed so I can have extra to put in the freezer. Simply cover the potatoes before the second baking with plastic wrap and freeze.