Mario Batali Under Investigation by NYPD for a Second Rape Case

Mario Batali is under investigation for an alleged rape at another one of his restaurants, one a woman claims happened the year before the alleged Spotted Pig incident ... TMZ has learned.

A Texas woman claims she was raped by Batali on Jan. 29, 2004, and according to our law enforcement sources ... she filed a police report with NYPD in March of this year.

The woman claims she was drinking at the bar at Babbo -- Batali's West Village eatery -- and around 2 AM, she went upstairs to use the bathroom. We're told the next thing she remembers is Batali on top of her, having sex with her ... and she was physically helpless.

Our sources say NYPD has an open investigation into the woman's claim.

As we told you, "60 Minutes" spoke to an employee from Batali's restaurant, Spotted Pig -- who claims Batali might have drugged her and sexually assaulted her in 2005. "60 Minutes" says NYPD is investigating that case as well.

Batali denied the Spotted Pig claim.