Clean and devein the dried peppers and place in a bowl with warm water. Let them soak there for about 20 minutes or until they’re soft. If you prefer to roast the peppers before placing them in warm water, do so on an ungreased skillet like they do in some parts of Mexico.
Drain the peppers, discard the soaking water. Place the peppers, roasted onion, garlic cloves and ½ cup of water in the blender. Process until you have a smooth puree. Pass the sauce through a fine sieve if needed to obtain a uniform texture.
Meanwhile, mix the (Masa) corn dough with the lard, chicken broth, baking powder and ½ cup of the pepper sauce and beat with your hands until it resembles a thick batter (if you have a Kitchen Aid, use it to do the work for you).
Clean the bananas leave with a wet paper towel and run the leaves slowly over a medium flame. The leaf will turn shiny and become soft and pliable.
Slowly run the banana leaves over the gas or electric stove as seen HERE to make them pliable. Cover a 9” X 13” baking dish or other rectangular ovenproof dishes with the leaves, leaving the excess part of the leaves draping outside the dish like flaps to cover the top part of the Zacahuil. Spread half of the prepared batter of (masa) corn dough at the bottom of the dish. After that, spread with the uncooked pork meat pieces, cover with the pepper sauce, and add the remaining half of the dough, spreading evenly. Fold the hanging banana leaves flaps, like if you were wrapping a package.
Now, place the whole baking dish in the Oven Baking Bag and close. Place it in a preheated oven at 350 degrees for about 2 ½ hours. The leaves will release a slightly smoky flavor while baking. After this time, open the bag and check if the meat is done. The corn dough should have a golden crust in the outside areas and the inside will be a little bit soft. If it needs more baking, cover and returns to the oven for a few more minutes.
When done, remove the bag and let stand for about 15-20 minutes to wait for the dough to firm up a little bit more.