In World War I slang, what name was given to corned beef?

Bully Beef.

In addition the Iron Ration was the emergency ration of bully beef, tea, sugar and biscuit. Carried by all soldiers in case of being cut off from normal food supplies.

In the Royal Navy it was known as "Sweet Fanny Adams", after a young woman who had been murdered and dismembered in the 19th century.

A recipe book I have mentions the corned beef/Fanny Adams story, only in this version of the tale, the unfortunate young lady perished after eating the contents of a contaminated tin of this particular meat product.

Bully Beef is not the answer I'm after.

Your joking shaky - this is the name used by the Australian as well as the British soldiers in the trenches. But I apologise if I've got it wrong - just have a look here.

http://spartacus-educational.com/FWWtrenchfood.htm
https://en.wikipedia.org/wiki/Digger_slang

Could you be looking for "Corn Willie" or "Corned Willie"? According to some websites, this was US Army slang for corned beef.

Once I found that reference, and searched for IT on google, a number of diary entries from WWI soldiers came up. Several of them also mention "Old Charley" as corned beef.

A letter home from Lawrence M., dated Sept 29, 1918 says, "what also is known in the states as corned beef but here it's 'corned willie' or 'old charley'; also salmon is 'deep sea turkey.' It's a small article of food here that doesn't get a syllable or two tacked to its name, ha!"

Read the whole letter dated Sep 29 1918 by Lawrence Mc.

[From fbrowncountygeneology.com 2003 article, no longer online]

We are talking slang terms here. I am not disputing that "bully beef" or even "corned willie" were slang terms for corned beef. There were probably others as well, including the one I read about recently. A nudge for you is that it was named after a certain animal noted for its speed and agility.

This isn't what you're looking for, but I found:
FRAY BENTOS
(1) Corned beef, bully beef, named after the prevalent brand. From the port in Uruguay of the same name, famous for meat-packing. (2) Very good, very well. From a corruption of the French très bien.
http://www.oxfordreference.com/view/10.1093/acref/9780199829941.001.0001/acref-9780199829941-e-18247

According to Larousse, corned beef was known to the troops as "monkey meat". (Perhaps that is how they became known as "troops"?!)

Found your source online too. Isn't it always easier to find when you have the answer.

BTW, the Larousse's entry for monkey is interesting. A few facts gleaned from it:
- Only vegetarian and fruit-eating species are eaten.
- Monkeys form part of the staple diet of several Amazon forest tribes.
- Ali-Bab thought macaque meat tasted like squirrel (not a compliment); Lévi-Strauss said stewed marmoset tasted like goose.
- Corned beef was called "monkey meat" in World War I slang in Europe. (I wonder what the etymology of that is.)
[From egullet.com 2003 article, no longer online]