So I gather you're confused as to what's the link between soldiers and biscuits?
It's a joke in Romanian, based on the homonimy of "biscuiţi" (pl. of "biscuit") with the imaginary 2nd person plural imperative of a verb "biscui" (to "cookiefy"). That verb doesn't exist, but the word sounds as if it were conjugated in that tense and person.
The full joke is:
Stephen the Great was leading his army. At a certain spot, he finds biscuits on the ground. He gathers them, analyses them and then says:
"Biscuiţi, soldaţii mei"
[cookies/cookiefy, my soldiers!]
And the soldiers reply:
"Biscuim, Măria Ta!"
[we cookiefy, Your Highness!]
It's what we Romanians call a "dry joke". Not much to laugh at.
