Many years ago I managed a Younkers department store restaurant. Younkers restaurants were best known for their Rarebit sauce covered hamburgers. The restaurants have long since closed and the newspaper articles leading up to the final days posted the rarebit sauce recipe. It was not the original, and many of my customers asked why it did not taste the same. Here is the original.

Younkers Rarebit Sauce

we made this 4-5 times per week

3# flour
1 1/4 qt vegetable oil
1 cup paprika
1/4 cup salt
1/4 cup dry mustard

mix together and cook in double boiler

Heat in a double boiler 3 gallons of whole milk to 160 degrees
Gradually add roux. Mix thoroughly until thick.

1 cup worcestershire sauce
1/4 cup tobasco
1/4 cup egg shade food coloring

7# shredded processed sharp cheddar cheese (we used Hoffman's Super Sharp)

Whip in 1/3 at a time.

1 1/2 cups of this sauce was poured over a char grilled hamburger on a toasted bun

Here is a reduced version of the recipe