Soak the corn husk in some hot water for 2 hours. Use a heavy bowl or pot to weigh down, set aside.
In a large bowl combine the masa harina, salt, and baking powder. Gradually add in the warm chicken broth and work in until dough forms. In another glass bowl, melt the shortening or manteca, then work well into the masa mixture. Cover with plastic wrap and set aside.
In saucepan, combine the clean tomatillos, onion, and chile serrano. Fill with enough water to cover, cover and bring to a boil. Reduce heat, stir and cook for an additional 10 minutes, just until tomatillos turn color. Drain the water and transfer to the blender, add cilantro and 1 teaspoon of salt. Blend until smooth. Transfer to a bowl and stir in the diced green chiles, taste for salt. Set aside.
Prepare a large steamer pot with water, set aside. Once everything is in place, shake of excess water from husks. Take one husk(about 5 inches across) and using the back of a spoon spread enough masa to cover the surface(not too thick). Add a strip of cheese and cover cheese with salsa verde mixture. Fold in the sides, then fold down the flap and wrap tightly with foil paper. Stand up in steamer pot with open side up. Reserve extra salsa verde to garnish cooked tamales.
Once all tamales are done, bring to a quick boil in steamer, then reduce heat to medium. Steam for 1 hour, checking for water every 30 minutes. After 1 hour, pull out 1 tamale and let cool slightly, if the husk pulls away easily from masa, they are done.If not, steam for another 30-35 minutes. Let tamales cool slightly before eating. Yields 15 to 18 large tamales. Garnish the tamales with extra salsa verde!