Tacos al Pastor (or Shepard's Style Tacos) are one of my favourite tacos EVER and I don't say that lightly. In the north of Mexico they are called 'Tacos de Trompo', because they are cooked in a vertical spit called 'trompo' (spinning top) similar if not identical to the one Kebabs are cooked on, with a piece of fresh pineapple and a big onion on top. The cooking method and the gadget were brought by Lebanese immigrants to Mexico in the late 1910 and early 1920's.