Bill Knapp's Au Gratin Potatoes

1 tablespoon chicken fat*
1 tablespoon flour
1 cup milk 
1 cup shredded cracker-barrel sharp (important!) cheddar cheese
about 4 med. potatoes, diced
1) make a roux with flour & fat. if I don't have fat, butter is darn close.
2)add milk, bring to boil and thicken for 1 min. Add cheese, stir, & remove
from heat.
3) meanwhile, boil potatoes until tender but still firm and drain.
4)mix with cheese sauce, top with paprika, and bake around 450 until top is
golden.

*Our emergency recipe book (which I wish I had) called for using chicken fat
from the tubs of precooked chicken we got everyday from the commissary in
the au gratin potato recipe. For the batches we made, probably ½ cup butter,
½ cup fat. If you ordered correctly every night, you never had to prep in
the restaurant from scratch.