These are a favorite of mine from the early days.  Easy to make ahead, and even freezable!

6 baked potatoes
1 t. grated onion
¼ c. evaporated milk
1 t salt
1 (3-oz.) pkg cream cheese — NOTE: This is a little package of cream cheese – Philly makes the 3 oz.
2 eggs
2 T butter
½ t pepper (white pepper optional)

Slit tops of baked potatoes and scoop out centers, placing them in large mixing bowl.  Mash with electric beater.  Add other ingredients and beat until fluffy. Pile into potato shells and store in fridge until ready to cook.  (Cover tightly and freeze at this point if you want to save them for much later. Thaw in fridge before baking, of course.)  Bake at 400° for 20 minutes or until lightly browned on top.