A crazed Bronx monster-mom was so hellbent on killing her two little kids that she used three different methods on the tragic tots, prosecutors said yesterday.

Lisette Bamenga, who pleaded not guilty, first allegedly spiked her children’s grape juice with windshield-wiper fluid, then tried to drown them in a tub. Finally, the 29-year-old schoolteacher used a stove to fill her Parkchester apartment with gas to finish off 5-year old Trevor Noel Jr. and his 4-month-old sister, Lillian, prosecutors alleged.

The grisly details were revealed at a Bronx Criminal Court video arraignment of Bamenga, who is in the psychiatric prison unit at Elmhurst Hospital, where she was committed after a suicide attempt.

Bamenga was enraged that her NYPD-cop husband, Trevor Noel Sr., fathered a child with another woman, sources have said.