Cream of Potato Soup (recipe over 100 years old )

3 potatoes
1 quart milk
2 slices of onion           
3 tablespoons flour           
1-1/2 teaspoons salt           
1/4 teaspoon celery salt           
1/8 teaspoon pepper           
2 tbsp. butter or oleomargarine  

Cook the potatoes in boiling salted water. When soft rub through a sieve. Scald the milk with the onion in a double boiler, remove the onion, unless the family likes it left in, add the salt, celery salt and pepper. Melt the butter in a small sauce pan, stir the flour into it and then add this mixture to the hot milk, stirring briskly. Cook for ten minutes over boiling water in the double boiler.  

A good creamed soup may be made from almost any vegetable, substituting vegetable pulp for the potato. Celery soup and corn soup are very good. With these and most other vegetables, the celery salt should be omitted. Onion salt is very useful.  

Creamed soups are very good made from skimmed milk if there is a supply in the house which should be used.