Soeng Bake's attack on her step-son came to light on September 14 last year, when the youngster refused to get changed with the rest of the class before a P.E lesson at East Dene Primary School, Rotherham, Sheffield Crown Court was told.
Prosecuting, Louise Gallagher, said the boy, who is now aged eight, 'expressed a desire to change in the toilet, rather than in public'.
After staff at the school noticed bruises on the boy's arms and legs, police, social workers and Bake, 42, were brought into the school for a meeting.
One of the boy's bruises, on his inner-left thigh, was particularly large that measured eight by 10cm.
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Initially, the boy told police he sustained the bruises when he fell over a piece of Lego, but eventually admitted the bruises were caused when his stepmother hit him.
Ms Gallagher said: "He said his mother hit him with a stick because he wouldn't eat his breakfast.
"He went on to say he had been sick lots of times on the table because he kept eating his breakfast when he was full, and she went to get a black stick."
The little boy said his stepmother put cream on his bruises after hitting him, and told him not to tell anyone what had happened.
The complainant and his baby brother were subsequently taken from Bake and put into foster care, the court was told.
In police interview, Bake admitted hitting the boy after becoming 'frustrated' with him for refusing to eat his breakfast.
Bake said she had previously been using the stick as a support structure for plants she was growing in the home.
She claimed disciplining a child with a stick was common-place in her native North Korea, and 'even teachers' would hit children with sticks, the court heard.
Bake, of Bethel Road, Rotherham pleaded guilty to one count of assault occasioning actual bodily harm at an earlier hearing.
Francis Edusei, defending, said Brick was 'full of anxiety and guilt' for her actions.
"The defendant indicates to me that her son had a habit of not eating his breakfast, which caused her a great deal of concern. She had taken him to the doctor's, who wasn't impressed because he's completely healthy," said Mr Edusei, adding: "By all accounts, she's had a very difficult life coming from North Korea.
"She sees her children three time a week and she's keen to be reunited with them."
Judge Robert Moore sentenced Bake to 12 months in prison, suspended for 12 months, and ordered her to complete a 20-day rehabilitation activity requirement to help her 'manage her frustrations'.
Judge Moore said: "You admitted your mistake and the two children are now with foster parents. Your contact with your two children is now closely monitored.
"This matter is to be marked with a custodial sentence because the circumstances were so serious."
He added: "But the overall situation does not require it to be immediate."