A woman shook the life out of the 12-month-old boy she was hoping to adopt to "stop him crying", a court has been told.
Laura Castle, 38, initially claimed Leiland-James Corkill accidentally fell off the sofa at her home in Barrow-in-Furness, Cumbria, in January 2021.
However, medics treating the baby in hospital raised the alarm when they found his catastrophic head injuries did not match her account.
The defendant continued to maintain Leiland-James's death was a tragic accident until last week when she admitted his manslaughter on the eve of her murder trial at Preston Crown Court.
Leiland-James was a "looked-after child" who was taken into care at birth, before he was then approved by authorities to live with Castle and her husband, Scott, 35, from August 2020.
Giving evidence on Tuesday, Castle told jurors that Leiland-James was "screaming" after breakfast on the morning of 6 January.
She told her barrister, David McLachlan QC: "I shook my beautiful boy. I just wanted him to stop crying."
Mr McLachlan asked: "How many times did you shake him?"
Castle replied: "I don't know."
Mr McLachlan went on: "How much force did you use to shake him?"
The defendant said: "I don't know but I would say a lot."
She explained Leiland-James hit his head on the back of the arm of the sofa and fell off her knee to the floor.
Castle said: "I picked him up. I just couldn't take the crying. I don't know who that person is and then it's like I realised what had happened and I thought he was winded.
"I picked him up and his hands were like stiff, then he went floppy. He was like gasping and I just though he was winded."
'I just wanted it to stop'
In tears, Castle accepted she had killed Leiland-James.
Mr McLachlan asked: "What went through your mind when you shook the life out of Leiland-James?"
Castle said: "Please stop crying, please stop crying. I just wanted it stop."
She said at the time she told her husband the boy had fallen off the sofa, but did not inform him about the shaking.
Mr McLachlan said: "Why didn't you tell the people trying their best to save Leiland-James's life what had happened?"
Castle said: "I don't have an excuse. I just panicked. I was just terrified of the consequences of my actions and ashamed."
Laura Castle denies murder and child cruelty, while Scott Castle denies causing or allowing the death of Leiland-James and also child cruelty.
The trial continues on Wednesday.