Bill Knapp's had a large menu and was known for soups, my favorite was the Bean Soup, hamburgers, fried or marinate chicken, biscuits, fried onion rings, and Au gratin potatoes. I found this web site which has different pictures of Bill Knapp's including a picture of their menu.
In the 1990's, my Aunt Irma liked to treat the family to dinner at Bill Knapp's for our birthdays. She liked the decent prices, the discount given to the birthday person, and the free chocolate or white cake given for birthdays. We always felt a little sinful when we order the Au gratin potatoes which were one of Knapp's signature dishes.
The original recipe I found for Knapp's Au gratin potatoes called for half a pound of margarine. I eliminated it and like the results just as well. Without the margarine, the milk has to be adjusted and increased to insure a creamy sauce. In 2004, fat was not the villain that it was in the 1990’s so I added back a half of a stick of butter and upped the cheese to one and a half cup of sharp Cheddar cheese.
LIKE BILL KNAPP'S AU GRATIN POTATOES
1/2 stick butter
Ingredients: Frozen Southern-style hash browns, Velveeta cheese, onion, sharp Cheddar cheese, milk, and butter.