55-year-old Rosa Baca faces life in prison without parole for the December 2018 attack on her live-in boyfriend, 38-year-old Jose Magana.
Baca initially told police her boyfriend came home after getting assaulted, but detectives found inconsistencies with her story.
They say after the brutal beating, she waited hours to call for medical help.
Baca is scheduled for sentencing on July 31.