How to Make It
Separate the cornhusks and discard the silk (be careful—the papery husks break easily when they are dry). Select 12 of the biggest and best-looking husks from the bunch and soak them in a large bowl or sink filled with warm water for 30 minutes to soften.
In a deep bowl, combine the masa harina and salt. Pour the warm chicken broth into the masa a little at a time, working it in with your fingers. In a small bowl, beat the lard with a handheld mixer until fluffy, add it to the masa and mix until the dough has a spongy texture. Cover and set aside.
In a blender, puree the cuitlacoche and cilantro with about 1 tablespoon of water until smooth. Add the mixture to the dough and fold in well. Season with salt and pepper.
To make the tamales, drain the cornhusks and pat dry with paper towels. Lay a husk flat on a plate or in your hand, with the smooth side up and the narrow end facing you. Spread a thin, even layer of the masa mixture over the surface of the husk with a spoon that has been dipped in water. Fold the narrow end up to the center, then fold both sides together to enclose the filling and pinch the wide top closed; the sticky masa will form a seal. Repeat with the remaining husks and masa filling.
Bring a large pot filled with 2 inches of water to a simmer. Stand the tamales up in a steamer or colander and put it into the pot, but don't let the water touch the bottoms of the tamales. Lay a damp cloth over the tamales, cover the pot tightly with a lid, and steam the tamales for 30 minutes over medium to low heat; keep the water at a low simmer. The tamales are done when the inside pulls away from the husks; they should be soft but still firm and not mushy. Turn off the heat, remove the pot lid and damp towel, and let the tamales cool in the steamer for 10 minutes. To serve, open the tamales carefully, leaving the husks on, and sprinkle each with a bit of the cotija cheese.
Dehydrated, powdered masa is often referred to as instant corn masa. Maseca is a popular brand and can be found in most grocery stores. The flour is made from cooked ground hominy and looks like white cornmeal.
Cotija is an aged strong-tasting and somewhat hard, dry cheese made from cow's milk. Named for the town of Cotija, Michoacan, where it originated, it is called the "Parmesan of Mexico," and is ideal for grating; available in most Latin markets.
Cuitlacoche is corn smut, a type of fungus that invades the growing ears of corn, causing the kernels to swell into gray or blue-black masses. Known as the "truffle of Mexico", it is considered a delicacy and has the same uses as mushrooms, with a much more complex flavor. It is available fresh or canned.