Place corn husks in a large bowl or pot. Cover completely with warm water and allow to soak for 30 minutes, until husks are soft and pliable. Keep covered in water until ready to use. Rinse and wipe clean before using.
Prepare the dough: In a large bowl, mix yeast with ½ cup of the warm water (or broth). Let rest for few minutes. Add cornmeal, remaining warm water (or broth), coconut oil, salt, baking powder, and turmeric. Mix by hand (or with an electric mixer) until dough is the consistency of cream cheese. Cover the bowl with plastic wrap or a damp towel. Set aside.
Prepare the sauce: In a sauce pan, over medium-high heat, combine water (or broth), chilies, tomatillos, onion, and garlic. Bring to a boil. Reduce heat to low and simmer 2 to 3 minutes. Remove from heat. Let cool. Transfer to a blender or food processor and purée. Set aside.
Prepare the filling: Place hibiscus flowers in a medium-size bowl and cover with warm water. Soak for 15 minutes until fully hydrated and soft. Rinse, drain, and squeeze out excess water.
In a large skillet, heat oil over medium heat. Sauté drained hibiscus flowers with soy sauce for 2 minutes. Add prepared red chili sauce, cumin, and sugar. Simmer over low heat for about 15 minutes, until hibiscus flowers are soft. Set aside.
Assemble: Remove corn husks from water. Clean and pat dry. Spread husk out, smooth side up, on work surface. Notice each husk has a narrow (tapered) end, a broad end, and two long sides. Using a spatula (or back of a spoon), spread a heaping tablespoon of prepared dough across the broad end of the husk in a thin even layer, ¼-inch thick, leaving the narrow end of the husk empty. Place a few spoonfuls of hibiscus filling into the center of the dough, leaving a border on each side. Wrap the tamale by folding the long sides together like a book. Fold over the remaining edge once more. Fold up the tapered end to close. (Tamales can be tied with a thin strip of corn husk or kitchen string).
Repeat above steps to assemble each tamale.
An alternative way to assemble the tamales: Cut a long rectangular piece of parchment paper. Spread the dough along the length of the paper, ¼-inch thick, and approximately 4 to 5-inches wide. Place filling in the middle, down the full length of the dough, leaving a border (of dough) on each side. Roll up the parchment paper lengthwise, to make a long roll of dough (with filling in the center). Unwrap and cut the rolled dough into 4-inch lengths. Place each piece in a corn husk. Wrap the tamale (as above) by folding the long sides over the dough, then fold up the tip of the husk to close.
Steam and serve: Use a large stockpot with a steamer basket. Fill stockpot with water just below the steamer basket. Line bottom of steamer basket with a few corn husks. Place tamales snugly in steamer basket so they stand upright (the top of the tamale or open end should be up). Extra corn husks can be placed in between tamales to keep them upright. The tamales should be snug but not overcrowded in the steamer as they will expand when cooked. Bring the water to a boil, then reduce heat to low and cover. Steam 30 to 45 minutes, or until dough is cooked through (be sure to add water to the pot to prevent burning). To check if done, unwrap a tamale. When the dough is cooked through, the tamale will easily pull away from the corn husk.
Remove tamales from steamer. Let sit for 5 minutes before serving.