rrecipe for SOS
make a basic white sauce out of flour, milk, butter, and salt/pepper.
throw in finely chopped bits of Carl Budding sliced beef.
layer over dry whote toast.
If you really want to be "authentic", you use dry milk powder, and butter flavored powder. reconstitute these with water before adding.
thus it could be carried in dry form anywhere, easily, and quickly "made up" in the field.
It's simple, cheap, filling, and easy to make which is why the Army/Air Force/Marines made it all the time.
and it's named because of two things.
Shit because the "sauce" doesn't look very appealing.
Shingle for the dry white toast.