• Start by rehydrating the corn husks. Place the corn husks in a large heat safe bowl, then cover with hot water and let sit for at least 15 minutes.

Make the Filling

• Place the dried guajillos and ancho chiles in a medium-sized saucepan over medium heat, and fill with enough water to cover by an inch. Let the water come to a boil, then once it reaches a boil, reduce the heat to low and let cook for 15 minutes. Reserve 3 ½ cups of the Chile soaking liquid.
• Once the peppers have softened, use a slotted spoon to transfer them to a blender, then add in the garlic cloves, black peppercorns, cumin seeds, fresh thyme, kosher salt and 3½ cups of the Chile soaking liquid (if you don’t have enough to make up 3½ cups, add water until you have enough). Blend until smooth. Taste the sauce for salt then adjust. Reserve 1 cup of the chile sauce then then pour the rest into a large Dutch oven.

  Add the beef chunks, then add 3 ½ cups of beef stock, stir, then cover and bring to a boil over medium heat. Once it reaches a boil, reduce the flame to low and let cook for 3 to 3 ½ hours, until the beef shreds easily. Use a slotted spoon to remove the beef, then use two forks to shred. Turn the flame up to medium, and let the sauce reduce for 12 minutes, then remove from the flame. Taste the sauce for salt and adjust,  then toss the shredded beef back into the sauce.

Make the Masa

• In a large bowl, whisk together the masa harina, baking powder, and salt. Add the lard to the stand mixer bowl fitted with the paddle attachment and whip the lard for 2 ½ minutes on medium speed. Reduce the speed to low, then alternate between adding the masa harina (1/4 cup at a time) and chile puree.

  Once all of the masa harina has been incorporated, pour in the chicken stock in a slow and steady stream. Turn the mixer off, then use a rubber spatula to scrape down the sides and bottom of the bowl. Gradually bump the speed up to medium-low and beat for 30 seconds then cover the bowl with plastic wrap and let the dough sit for 20 minutes to fully hydrate.

Assemble the Tamales

• Reserve 18 corn husks for the tamales then take a couple of extra husks and and rip 36 (¼-inch-wide 8-inch long) strips. Take two strips and tie them together at the ends, so you’re left with 18 strips (about 14 to 15 inches long). We’ll be using these to tie the tamales.

  Grab a large corn husk, and add about ⅓ cup (3oz/85g) of the masa. Use a spoon, offset spatula, or wet fingers to spread the masa down into a square, leaving an inch of space on the top, left and right side and at least 2 to 2 ½ inches of space on the bottom. Add two tablespoon of the filling to the center, then fold the right edge of the masa over to meet the left edge and press the edges down to seal. Tuck left side of the husk into the right side, then wrap the right side of the husk around to create a tube, then fold the bottom upwards. Tie a strip around the bottom of the tamal, to secure the bottom fold, then repeat the process with the remaining tamales.
• Add 5 to 6 cups of water to your steamer pot, then add the steamer insert and then place your tamales inside vertically, open side up. Place the lid on and bring the water to a boil (about 10-12 minutes) then reduce the flame to medium-low and let cook for 1 hour and 25 minutes to 1 hour and 40 minutes, until the masa cleanly pulls away from the husk. At the 1 hour mark, check the bottom of the pot for water, and replenish as needed. If the water for the steam runs out, the bottom of the pot will burn and get ruined.

  To reheat, steam for 30 to 40 minutes until fully warmed through.