​As her trial was set to begin Monday, a deranged mom pleaded guilty to smothering her 1-year-old son in a Midtown burger joint.

Latisha Fisher, 38, copped to one count of first-degree manslaughter in exchange for 18 years in prison as part of a plea deal.

The mom, who suffers from schizophrenia, faced up to life in prison if convicted of the top charge of second-degree murder.

Fisher was arrested in March 2015 after she was discovered in the bathroom of 5 Boro Burger, holding her son, Gavriel Fisher, who was foaming from the nose and turning blue, authorities said.

“The devil made me do it,” Fisher allegedly told responding cops. “I was afraid that someone was going to eat him,” she bizarrely claimed.

“I was protecting him. I put him to sleep with my hand,” she said.

Defense lawyer, Bryan Konoski, didn’t immediately return a request for comment.

Fisher is due back in Manhattan Supreme Court Nov. 20 for sentencing.