Place the pork pieces in a large pot with the onion half. Add water to cover the pork along with 1 tablespoon of the kosher salt and the pepper.
Bring the water a boil and then reduce to a simmer for 3 hours. Remove pork from water and shred. Reserve 4 cups of the pork broth for making the masa.
While pork is simmering, put the ancho chile in small pot with 1 cup of water. Bring to a boil, then simmer for 30 minutes. Remove from water, deseed, and remove stem. Blend it in a blender with 1/4 cup of new water until it is completely puréed.
In a large pot, add puréed ancho chile, remaining 2 teaspoons salt, 1/4 cup of pork broth, and shredded pork. Mix until combined. Heat for a few minutes to combine the flavors. Remove from heat and set aside.
Soak corn husks in hot water for 15 to 20 minutes while you make the masa.
For the masa:
In the bowl of a stand mixer, beat the lard with baking powder until fluffy, at least 10 minutes.
Transfer to a large bowl and add masa, 3 1/2 cups of the reserved broth, and salt. Mix by hand until a sticky dough forms. (Add the remaining 1/2 cup, little by little, if the dough is too dry.)
Turn the stand mixer back on low speed (with nothing in the bowl) and slowly add small amounts of the hand-mixed dough back in. You'll mix for two to three minutes total, until a paste-like consistency is formed.
Remove the corn husks from the water and wring them dry. Lay them on a hand towel and sort the husks: Pick out those of similar size husks for consistent tamales (you'll use the others to tie the tamales and to line the steamer basket).
Place the husk in the palm of your hand and using a spoon, spread the masa paste on the half of the husk that is laying in your hand in a very thin layer. Add three to four tablespoons of pork filling and fold up the husk. Using small pieces of husk, make a tie around to hold the husk closed.
Add 4 cups of water to the bottom of a large steamer. Line the bottom of the steamer with small and broken pieces of the husks, then begin layering the tamales in.
Once all the tamales are in, use a plastic grocery shopping bag to cover all the tamales. Cover with a dish towel, then cover the pot with the lid.
Steam for one hour and then turn off the heat. Allow the tamales to sit in the steamer for an additional hour after the heat is turned off.
Serve with refried beans and Janet's Salsa Verde. https://food52.com/recipes/69594-janet-s-salsa-verde