Let them eat crumbs!

Angry NYPD officers called Mayor de Blasio a liar Monday as he shoveled pastry crumbs into his mouth during a leisurely Brooklyn breakfast before heading to his traditional morning workout.

The protest by around 100 cops in Park Slope came after the Patrolmens Benevolent Association announced it had opted for arbitration upon reaching in impasse in contract negotiations with the city.

The angry mob screamed at de Blasio through the windows of Colson Patisserie as he, Chirlane McCray and a City Hall spokesman dined inside.

De Blasio enjoyed a pastry so much he poured the crumbs off his plate and ate them out of the palm of his hand.

When de Blasio ventured across Ninth St. to the YMCA gym at around 8:20 a.m., the rowdy cops surrounded him from all sides hurling insults and blowing whistles.

Who has a job where you can show up whenever you want? We want him to come to the bargaining table and negotiate realistic with us, said PBA President Patrick Lynch.

He wakes up at the crack of noon and goes to work.

The union and the city are fighting over a two-year contract covering Aug. 1 through July 31, 2019. Lynch took particular exception to what he has called dramatic increases in out of-pocket health benefit costs and a removal of the PBA Annuity Fund for current and future members.

Lynch and de Blasio are frequent foes.

In 2015, Lynch protested a previous decision by an arbitration panel that gave rank-and-file NYPD cops a 1% per year raise.

The arbitration ruling was roughly the same as what the city had offered.