How to make cow head barbacoa

“What do you want with a cow head?” asked the farmer selling beef at the Union Square Greenmarket. “We don’t sell cow heads here in New York—they’re illegal.”Not to be deterred, I got on the phone and called my local butchers. It was the same conversation each time. First, they’d express shock and disgust at my query. And then they would curtly inform me that they could not ever, no way, no how