How to Make It
Preheat the oven to 350°. In a 6-quart pot, cover the pork with the water. Add the garlic, bay leaves, onion, pepper and 1 tablespoon of the kosher salt, and bring to a boil over high heat, skimming the surface once or twice. Cover and simmer the pork over low heat until cooked through, about 30 minutes. Using a slotted spoon, transfer the pork to a bowl and let cool, then finely chop. Reserve the broth; you should have about 7 1/2 cups.
In a large bowl, combine the masa harina with the vegetable shortening, baking powder and the remaining 1 tablespoon of salt. Add 4 cups of the reserved broth and knead the masa with your hands until a soft, sticky dough forms.
In a very large skillet, bring 3 cups of the reserved broth to a simmer over moderately low heat. Whisk in the mole until the sauce is smooth; whisk in the remaining 1/2 cup of broth if the sauce seems too thick. Add the pork and simmer over moderately low heat for 10 minutes, stirring occasionally.
With wet hands, spread a little less than half of the masa dough on the bottom of a 9-by-13-inch glass or ceramic baking dish. Spoon the pork mole on top. Cover with the remaining masa dough, spreading it to completely enclose the filling. Tightly cover the baking dish with foil and bake for 1 hour, or until the crust is puffed and set and the filling is bubbling. Remove the foil and bake the tamale for 15 minutes longer, or until golden. Let stand for 10 minutes, then serve with sour cream, cilantro, lime wedges and sliced scallions.
Masa harina is the flour made from finely milled hominy (dried corn kernels that were soaked in lime) and is used for making tortillas and tamales. It is available at Latin markets and many supermarkets.