A Kansas mom was sentenced this week to 20 years behind bars for her role in the savage beating death of her 2-year-old son — who was killed when he refused to eat a hot dog, reports said.

Elizabeth Woolheater pleaded guilty in August to second-degree murder and two counts of child abuse for thrashing Anthony “Tony” Bunn on May 4, 2018.

The tragic toddler died two days later from his injuries.

“Tony was under your charge. And your job was to raise him and protect him,” Judge Jeff Syrios told Woolheater at her Friday sentencing. “You failed him in the very worst way possible.”

At the time of her arrest, Woolheater, of Wichita, told authorities that she “lost it” when Tony refused to swallow pieces of hot dog she gave him for breakfast — so she slapped him across the face and hit him again while her boyfriend, Lucas Diel, held the food in the boy’s mouth, according to an affidavit released in the case.

Woolheater then told police that she heard Diel hitting Tony repeatedly after she left the room and saw her son with a bleeding and swollen face, a broken front tooth and a cut on his lip when she returned.

Anthony’s maternal grandfather, Zak Woolheater, who previously had custody of Bunn, said his grandson was “the most amazing kid you will ever see.” He said the family first suspected he was being abused in October 2017 when they saw bruises and marks on his head and body. Zak told local media: “We took action, we took him to Wesley hospital and reported suspicion of child abuse.”

Records show his abuse was reported to the state’s child welfare agency seven months before he died, but the Department for Children and Families didn’t follow through on key steps that might have saved him, Kansas.com reported.

The DCF social worker assigned to him, Kena Battle, was also the social worker for Evan Brewer, a 3-year-old Wichita boy whose body was encased in concrete in September 2017 months after he died from horrific abuse.

Diehl — who claimed Bunn hurt himself by falling out of bed — was already convicted of second-degree murder and is serving a nearly 49-year prison sentence.