An online promotion by the George Pub in Stockton-on-Tees "trivialised" a serious issue, the Advertising Standards Authority (ASA) said.
The pub claimed the post was meant as a joke and attracted positive comments.
The ASA said the ad was "not prepared in a socially responsible manner."
Parmos are a Teesside fast food made from a piece of chicken or pork in breadcrumbs which is then deep fried and covered in bechamel sauce.
The promotion, which featured on the pub's Facebook page in May, resulted in a complaint to the ASA on the grounds it encouraged domestic violence.
An ASA spokesman said: "We considered that the phrase 'punch your ex in the face' referred to domestic violence and was likely to cause serious offence.
"We considered that referring to domestic violence in an advert for a fast food dish trivialised and condoned domestic violence and concluded that the ad was not prepared in a socially responsible manner.
"The ad must not appear again in its current form. We have also told the George Pub and Grill not to trivialise or condone domestic violence in its advertising."
A Teesside pub "condoned domestic violence" when it asked customers if they would "punch your ex in the face for a parmo", the advertising watchdog has ruled.