Place cornhusks in a very large, deep bowl or other large container or pot. Cover the husks with very hot (but not boiling) water. Submerge the husks into the water, allowing the trapped air to bubble up. Place a plate or pan on top of the husks to keep them completely submerged. (I like to weigh it down with a heavy 28-ounce can placed on a plate.) Allow the husks to stay in the hot water for 2-3 hours, or until pliable.
While husks are soaking, prepare the tamale dough. Place the lard or shortening into the bowl of a stand mixer fitted with the paddle attachment. Beat until creamy, then add the salt and baking powder. Beat on medium-high speed until light. (It won't really get fluffy if you use lard.)
Stop and scrape down mixer as needed. With mixer running on low speed, add the masa (fresh or reconstituted) to the mixer in three additions, beating well after each addition. Add chili powder, if using. Raise speed to medium-high and beat for 1-2 minutes until well-combined. Stop and scrape down.
With mixer running on low, slowly add 1 cup of the broth. Keep beating until smooth. The batter may be ready at this point, but it may need more broth. Test by dropping a small amount of batter into a cup of cold water. If it floats, the batter is ready. If it sinks, add a little more broth and beat again for 1-2 minutes on medium-high heat. Test again. The batter texture will be like a thick cake batter – spreadable, but not at all runny. It should hold its shape when spread onto the cornhusks.
Get the steamer ready. (I use the strainer insert for my stock pot.) Place a steamer basket in the bottom of a stock pot or other tall pan. You may need to work in batches depending on the size of the pot. If you don't have a steamer basket, you can place some small ramekins in the bottom of the pan and place a few layers of cornhusks or even a layer of aluminum foil pricked a few times with a fork to allow for air movement. The tamales need to be elevated for even cooking. Furthermore, the tamales will need to stand up as they cook, so it may be necessary to fill up any empty spaces with extra cornhusks folded over or balled up aluminum foil.
Prepare ties to secure the tamales by cutting string or thin strips of the husks into 8- to 10-inch pieces. You will need between 30-32.
Remove the cornhusks from the hot water and pat dry. Carefully separate the husks, trying not to tear them. Choose the largest, most intact husks. Count out 30-32. If the husks are narrower, count out enough to double up, as needed.
To assemble the tamales, work with one at a time, lay a husk out on a clean counter or cutting board with the tapering end facing toward you. Spoon 1/4 cup of the batter on the husk and spread it out to make a 4-inch square, leaving a border of 1 1/2-inches at the tapered end and a 1-inch border along the sides. Depending on the size of the husk, the borders may be a little wider. If needed, use two husk overlapping each other for a wider area.
Spoon a rounded tablespoon of the filling down the center of the batter. Using the husk as handles, pull the long sides together in the center over the filling. Bring the edges together and fold together over the filling in the same direction. Fold up the bottom of the husk to close up the bottom of the tamale. If needed, wrap another small husk around the tamale to ensure the filling doesn't leak out, or if there are any splits in the husk. Use the string or husk strip and tied around the tamale to secure it, but not too tightly. The top will remain open.
As you work, place the tamales in the steamer with the open ends facing up. The tamales will expand as they cook, so leave a little space between them and don't pack too many into the pot. (See note above about filling any empty spaces to keep tamales upright.)
Place a little water in the bottom of the pan if you haven't added it already. Turn heat to medium and steam tamales for 60-75 minutes. Add more water as needed so the pan doesn't boil dry. Check about every 15-20 minutes.
You'll know the tamales are done when the husks come away from the tamales easily. Turn off heat and allow tamales to stand in the pan for 10 minutes so they can firm up.
Serve immediately or cool completely and store in refrigerator or freezer. Re-steam refrigerated or frozen tamales before serving. (It won't take as long as the initial steaming time – just until heated through.)