@izzythepush,
I just used ground beef when I made it, I think that's what they used in the Army too. The picture looks like ground beef. Anybody who's been in the US Army has eaten SOS.
Here is a recipe I found that looks good:
SOS (MILITARY STYLE CREAMED
BEEF)
1 pound ground beef
1 medium onion, chopped
1 tsp. Crisco or oil
salt and black pepper, to taste
3 tablespoons flour
2-1/2 cups milk (more if you like it thinner)
[I'd add a little Worcestershire sauce.]
6 slices buttered toast or biscuits
Add the teaspoon of oil or Crisco to hot, deep skillet along with the ground beef. As beef begins to lose raw look, add the chopped onion, salt and pepper.
Reduce heat and simmer, stirring often, until meat is completely cooked. Sprinkle flour over top and stir into meat and onion mixture until totally absorbed.
Slowly add milk, stirring constantly, until thickened. Taste and adjust salt and pepper.