Soak the corn husks in hot water, in a large pot or in your kitchen sink. Place a plate over them to weigh them down so they are completely submerged. Let them soak for at least an hour.
To make the filling, place the diced potatoes in a medium pot with salted cold water. Bring to a simmer and cook for about 6 min. or until the potatoes are slightly tender. When the potatoes are cooked, remove from the heat and pour the cup of peas into the water with the potatoes and let sit for 30 sec. Drain and set aside.
To make the adobo, bring a small pot of water to a boil. Remove the stems and seeds from the chiles and drop them into the water. Turn heat down to the lowest setting and let the chiles sit in the water for 10 min. Remove the chiles from the water and place in blender. Reserve ½ cup of the chile soaking liquid. Add the garlic, onion, oregano, cumin, cloves, cinnamon, white vinegar, and ½ cup of soaking liquid to the blender and process until smooth. Season with salt and pepper.
Pour the adobo on the cooked potatoes and peas, adjust seasoning, and mix well.
To make the dough, beat the vegetable shortening, on medium-high speed, with an electric mixer, until it has doubled in size and is nice and fluffy, about 3 minutes. Add the baking powder, salt, and beat for 1 minute to incorporate into the shortening.
Add half of the masa harina then add half of the vegetable stock. After it is completely incorporated, add the other half of masa harina and vegetable stock. Beat at low speed, until thoroughly mixed. It should have the consistency of a thick cake batter. If necessary, add more vegetable stock until you reach that consistency. Taste the dough, and add more salt if necessary. It should be a little bit salty.
For lighter and fluffier tamales, let the dough rest for an hour in the refrigerator. Remove the dough from the fridge and rebeat it, adding enough liquid to get it to the consistency it had before.
Remove the corn husks from the water and set on paper towels. Reserve the largest husks to wrap the tamales and the small ones to line the steamer.
To set up your steamer, fill the bottom with water making sure the water is not touching the steamer rack. Line the rack and sides of the steamer pot with corn husks. Set aside.
To wrap the tamales, pull 24 pencil thin strips off of the corn husks and set aside. Take a husk and dry off the excess water with a paper towel. Place the husk in your hand with the tapered side away from you and the smooth side up. Using a spoon, spread 2-3 tbsp. of the dough (¼ inch thick) onto the corn husk, forming a 3 - 4 inch square. Leave a border of at least ¾ inch on each side of the square.
Place 1 ½ tbsp. of the filling in the center of the dough. Bring the two long sides of the corn husk together, this will cause the masa to surround the filling, and roll them in the same direction around the tamal. (If the husk is too small, fold one of the long sides towards the center, and then fold the other long side on top.) Fold down the empty tapered section of the corn husk, forming a closed bottom. This will leave the top of the tamal open. Tie with a corn husk strip to secure the bottom of the tamal.
Place the tamal in the steamer vertically leaning against the side of the pot, with the open end on top. Repeat this process until you run out of dough and all the tamales are in the steamer. Cover them with a layer of corn husks. If the steamer is not full, fill the empty spaces with more corn husks. Cover the pot and bring the water to a boil. Turn heat down to medium and cook for 40 minutes. Check the tamales, when they separate easily from the corn husk it means they are done. If they are not done, steam for 10 more minutes and check again. (see notes for pressure cooker instructions)
Remove steamer from the heat and let sit covered for 10 minutes. Uncover and let cool for at least an hour. Don’t be alarmed if the tamales seem really soft. As they cool, they will firm up.
Serve with some salsa, or pop in the fridge until ready to use. They last in the fridge for about 5 days in an airtight container. Alternatively, pop into a ziplock bag and store in the freezer for up to 6 months