Submerge the corn husks in water and let soak. This will make them more pliable and less likely to tear.

In a medium bowl, stir together the corn masa and the warm water. Set aside to cool for 10 to 15 minutes.

Meanwhile, using an electric mixer, beat together the shortening, salt, and baking powder until the mixture is light and fluffy, about 1 minute.

Add the cooled masa and water mixture and beat at medium-low speed until well combined. Increase the speed to medium and beat for another 2 to 3 minutes. If the mixture seems dry, add up to ½ cup additional (cold) water, 1 tablespoon at a time, until the desired texture is achieved.

To make the tamales, spread about 1/3 of a cup of the dough on a corn husk, making a rectangle near the flat edge (opposite the pointed end). Leave a bit of space, ½ inch or so, at the top so that the dough doesn’t spill out when it expands during steaming. Press the dough into an even layer about 1/8-inch thick.

Spoon about 2 tablespoons of your filling mixture onto the dough in a line down the center. Fold in the sides of the tamale, enclosing the filling with the dough and the dough with the corn husk. Fold the pointed end up toward the top. Tear off a long strip of corn husk (I tear these off of very wide husks and/or tear up husks that are too small to use for tamales) and use it to tie up the tamale packet.

Stovetop: Place a steamer basket in a large pot filled to just below the basket with water. Cover the pot and bring the water to a boil. Put the filled tamales in the steamer baskes with the open ends pointing up. Cover the pot again and steam for 30 to 40 minutes.
Instant Pot: Put about 2 cups of water in the bottom of the pot. Place a steamer basket in the pot and then place the tamales in the steamer basket, standing on end (open ends up). Cover the pot, turn the valve to the sealing position, and pressure cook for 20 minutes. Quick-release the pressure and remove the tamales.

Serve hot with extra sauce if desired.