Jack Hughes, 24, hurled the treats at Alison Stevenson in temper after being accused of stealing them.
Although they hit the woman on the head she was uninjured.
The incident occurred in April last year at the Spar shop in Main Street, Camelon, close to Falkirk Sheriff Court where Hughes was sentenced for the crime yesterday.
Prosecutor Rachel Wallace said Hughes had entered the shop around 10am and came to the attention of Ms Stevenson "due to his loudness".
Ms Wallace said: "She watched him on CCTV to monitor his behaviour. She believed she saw him trying to steal and approached him.
"He became argumentative and said he wasn't trying to steal anything. Because of his demeanour she moved away from him with the intention of calling the police.
"As she walked away he threw a bag of cookies at her, striking her to the head."
Sheriff Derek Livingston said: "Isn't that what British people call biscuits?"
Hughes, of Shieldhill, who appeared by video link from Low Moss Prison, pleaded guilty to assault.
Solicitor Lynn Swan, defending, said: "I don't know if they were biscuits or cookies, but he was angry and he threw them at the lady and he shouldn't have done.
"He did have enough money for the cookies, or biscuits, he wasn't going to take them, and he threw them at her in temper and shouldn't have."
In a separate incident, Hughes admitted stealing an Xbox from "a former friend" at an address in Maddiston.
Sheriff Livingston jailed Hughes for 120 days.