Soak husks and make the filling

1. Cover the corn husks with very warm water. Weigh them down with a plate and soak 30 to 60 minutes, until soft and bendy. Drain, rinse off any silk, and pat dry so they’re damp but not dripping.
2. Add the water, onion, garlic, and chicken thighs to a pot. Bring to a gentle simmer over medium heat, then cook 18 to 22 minutes until the chicken reaches 165°F / 74°C in the thickest part. Transfer the chicken to a bowl, and reserve 1 cup / 240 ml of the hot cooking liquid.
3. Remove the stems and seeds from the guajillo and ancho chiles. Cover the chiles with hot water and let them soften for 15 minutes. Blend the softened chiles with the reserved cooking liquid, the onion and garlic from the pot, cumin, oregano, and salt until very smooth.
4. Heat the oil in a skillet over medium. Cook the chile sauce for 5 to 7 minutes, stirring often, until it darkens slightly and smells rounded instead of sharp. Shred the chicken, stir it into the sauce, and let the filling cool until warm, not hot.

Mix the masa

1. In a medium bowl, whisk together the masa harina, baking powder, and salt.
2. In a large bowl, beat the lard for 2 to 3 minutes until lighter in color and fluffy. Add the masa mixture and the 3½ cups / 840 ml warm broth in 3 additions, beating between each one, until you have a soft, smooth dough that spreads like thick hummus or cake batter. If it feels stiff or cracks when you smear a spoonful, beat in the extra ¼ cup / 60 ml broth a little at a time.
3. Let the masa stand for 10 minutes, then stir once more. It should feel light and easy to spread, not dry, crumbly, or runny.

Fill and fold

1. Lay a husk smooth-side up with the wide end near you. Spread about ¼ cup / 60 ml masa into a rectangle about 4 by 5 inches / 10 by 13 cm, leaving a bare border around the sides and the narrow end.

2. (Optional) Upgrade: Save a little extra red chile sauce and spoon just a small amount over the shredded chicken before filling the tamales. It gives the center a deeper chile flavor and keeps the filling tasting juicy without making it wet enough to loosen the masa.

3. Spoon about 1½ tablespoons / 22 ml filling down the center. Fold one long side over the filling, fold the other side over it, then fold the narrow end up. If a husk is narrow or torn, overlap a second husk behind it like a patch.
4. Repeat with the remaining husks, masa, and filling. Stand the tamales upright with the open ends facing up as you work.

Steam and serve

1. Fill the bottom of a tamale steamer, or a large pot with a steamer basket, with water just below the rack. Line the rack with a few extra husks, then arrange the tamales upright with a little space between them. Cover with a layer of damp husks or a clean damp towel, then put on the lid.
2. Steam over medium to medium-high heat for 75 to 90 minutes, checking the water level after 45 minutes and adding more hot water as needed so the pot never runs dry. You want steady steam the whole time.
3. Check one tamal: the husk should peel away cleanly, the masa should look matte rather than wet, and it should hold its shape but still feel tender. If it sticks to the husk or looks glossy and pasty, re-cover and steam 10 to 15 minutes more.
4. Turn off the heat and let the tamales rest, covered, for 15 minutes before serving. That short rest helps the masa finish setting, so the texture turns plush instead of sticky.