Preheat oven to 400°.
Rub potatoes with oil and place on baking sheet. Bake for 1 hour or until thoroughly cooked. Lower oven heat to 350°.
Carefully slice potatoes in half lengthwise. Leaving a small rim of potato intact for support, scoop out insides of potatoes into a bowl.
Add all other ingredients to bowl and mix until combined. Put potato shells back on baking sheet. Evenly distribute potato-cheese mixture between potato shells.
Bake an additional 15-20 minutes.
Optional: Add ham, green onions, bacon, broccoli, etc.