A school dinner lady was warned she is facing prison for stealing £60,000 from the school where she was head cook.
Paula Kester took the money from St Hild's School, in King Oswy Drive, Hartlepool, over four years.
A jury found her guilty of the offences on Wednesday after she denied four counts of theft at her trial.
The cash came from pupils' dinner money, Teesside Crown Court heard.
Each pupil paid for their dinners by putting cash into pre-payment card machines at the school.
Kester was responsible for collecting the money from the machines - sometimes as much as £1,200 a day - and preparing it to be banked.
She would keep some of the money or, on several Fridays, she kept all of it, the court heard.
Prosecutor Martin Towers said Kester was able to get away with the thefts because no one checked a record produced by the machines of how much money had been received.
"There was a large gap in the school's processes," Mr Towers told the court.
"The machines produced a printout of how much money they had taken that day,
"No one at the school compared that printout to the amount declared by Ms Kester.
"It is the prosecution's case that only she had the opportunity to create the false record and take the money.
"The system, you may feel members of the jury, was inadequate, it was comparatively easy for the head cook to abuse the trust placed in her and take advantage of it."
Investigators found £20,000 in cash had been put through Kester's bank account over the four years.
She claimed the money was from lottery wins, car sales, and an accident pay-out cheque which she said had to be 'turned into cash to pay in'.
Mr Towers observed there was no evidence of any of those transactions.
Kester, 53, of Percy Street, Hartlepool, was convicted of four charges of theft between September 2012 and April 2016.
Judge Peter Armstrong adjourned passing sentence for the preparation of a probation report.
"All sentencing options remain open," the judge told Kester. "That includes custody and you should prepare for that."
Kester was bailed to return to the court to be sentenced on Thursday, October 4.
A Hartlepool Borough Council spokesperson said: “As soon as we became aware of an issue an investigation was launched and the matter was subsequently reported to the police.
"Paula Kester was dismissed from her job with the Council in 2016.
“Procedures relating to the collection of dinner money by the council’s school meals service have been reviewed and we are confident that such a situation could not occur again.”