The boy and girl, whose names were not released because they are under 18, were making toast when he became angry at her for repeating a request for apricot jam, The Local.es reported Monday.
The Ideal newspaper in Granada reported the girl suffered only a bruise on her forehead.
The girl told police the incident was part of a pattern of aggressive behavior from her boyfriend, who lives with her and her mother, the report said.
The boy's family told the court he kept poor company and was known to abuse drugs.
The boy was sentenced to one year of probation and ordered to undergo anger-management training. He was warned he could face time in a juvenile detention center if he violates the terms of his probation.