I'm assuming it's real head meat, cuz ordinary beef doesn't act this way. The torta de barbacoa at La Mexicana bakery is something else. They bake their own bread - a significant plus, hence the other tortas are good - but when you slow-cook meat until it melts, and render it crispy afterwards, you touch my nerve center. This is the ideal.
I do add Valentina hot sauce at home, though it is already graced with a coupla hot chiles.