Quick potato soup

2 cups thinly-sliced raw potatoes
1/4 cup finely-chopped onion
1 1/4 cups boiling water
1 1/2 cups milk (may be partly evaporated milk)
1 tablespoon margarine
3/4 teaspoon salt

Add potatoes and onions to the boiling water.
Cover, and cook for from 14 to 20 minutes, or until potatoes are tender.
Mash the potatoes slightly with a fork to thicken the soup a little, if desired.
Add milk, margarine and seasoning.Heat to serving temperature.
Top each serving with a dab of sour cream and sprinkle with finely cut parsley.
Yield: 4 servings, 1 cup each.