Ex-'Real Housewives' Star -- I'll Take That Fancy Steak, To Go

Former "Real Housewives of New York" star Jill Zarin broke one of the golden rules of fine dining at the opening of a fancy steakhouse in NYC -- she asked for a doggie bag.

Zarin made the gourmet goof-up at the opening of NYY Steak in midtown Manhattan last week ... alongside the likes of Kris Jenner, Christina Milian and James Lipton.

We're told some NYY staffers were taken aback by Zarin's faux pas -- since most food snobs frown on great meats becoming leftovers.

Then again, Jill does have a dog. A tiny one, but still.