Wolfgang Puck Sued -- Your Waitress Smashed My Skull ... Now Pay Up!

Eating at Wolfgang Puck's restaurants can be a real headache -- just ask a woman who says she was dining at one of Wolfgang's D.C. locations ... when a waitress smashed her in the head with a pitcher ... and now she's suing the famous chef.

Tamara Mason-Williams filed the lawsuit in L.A. County Superior Court, claiming she was eating at Wolfgang's The Source Restaurant back in April ... when a waitress walloped her dome with a "heavy metal water pitcher."

Tamara says the incident left her with a nasty concussion -- and Wolfgang's restaurant is 100 percent to blame because of its "negligently trained" staff.

She's now suing for an unspecified amount in damages for lost income and medical expenses.