Pierce each potato several times with a fork and microwave the potatoes on HIGH until they are tender throughout (about 20 minutes depending on your microwave.) You can also bake or boil the potatoes until tender if you prefer. Let potatoes cool a few minutes.
Peel off skins (and discard) and add the potato flesh to a large mixing bowl along with the green onions, fat-free half and half, sour cream, butter or margarine, and garlic.
Beat on low speed until fairly smooth and blended. Add salt and pepper to taste.