Step 1

To prepare the corn husks, submerge in hot water for 45 to 60 minutes to make pliable. Select the 12 largest husks and rinse well. Pat dry husks and place in a sealed container to retain moisture. Set aside.

Step 2

For the filling, in a medium bowl, place diced mushrooms and toss with 1 teaspoon salt. Let sit for 30 minutes. Transfer to a colander and rinse under cold water. Pat dry mushrooms with a tea towel or paper towels. Set aside.

Step 3

In a nonstick skillet, warm oil over medium-high heat and sauté onion for 5 to 7 minutes or until translucent. Add Poblano pepper and sauté for 1 to 2 more minutes or until pepper is bright green. Add corn kernels, epazote, cured mushrooms, and water. Reduce heat to medium-low and simmer for 15 to 20 minutes or until water has nearly evaporated. Add remaining ¼ teaspoon salt. Remove from heat and reserve.

Step 4

For the batter, in a large bowl or stand mixer, combine corn masa flour, baking powder, and salt. Mix well. Add vegetable shortening and incorporate. Add water and continue mixing until the batter is uniform in texture.

Step 5

To form the tamales, using the back of a large spoon or spatula, place about 3 to 4 tablespoons of batter in center of corn husk. Spread batter evenly across the wide end of the husk. Place about 2½ tablespoons of filling in the center. Gently roll husk over to surround the filling. Fold the bottom under to finish forming tamal. Repeat until all 12 tamales are formed. In groups of 3, gently tie tamales together using kitchen twine or bound strips of surplus corn husks.

Step 6

To cook tamales, into a large steamer pot, place tamales upright on their folded ends. Fill empty space with a heat-resistant cup or mug to ensure tamales stay firmly in place. Add at least 2 inches of water to the bottom of the pot, making sure the water line is below the steamer basket. Cover and steam for 35 to 40 minutes, adding more water to the bottom of the pot as needed. Remove from heat and uncover. Let tamales rest in pot for at least 15 minutes before serving.