Step 1Place the tomatoes and water in a medium pot and boil for 20 minutes; the tomatoes will be very soft and almost falling apart. Remove from heat and puree; the puree will be somewhat thick.
Step 2Strain the tomatoes back into the pot, discarding the seeds, and stir in the mole paste until the paste is fully incorporated.
Step 3Heat the mole mixture over medium heat and stir in the chicken broth, salt and chocolate until dissolved. Increase the heat, stirring constantly, until the mole comes to a boil. Remove from heat and set aside.
Step 1Beat the lard vigorously until soft, then add the masa and baking powder until fully incorporated. Slowly stir in the water, a little at a time, until the masa is smooth and soft, and will spread easily onto a banana leaf.
Step 2Pat the leaves dry and cut into rectangles approximately 12 inches by 10 inches.
Step 3Smear about 3/4 cup of masa across each square and place a generous ¼ cup of chicken and 3 to 4 tablespoons mole right in the middle of the tamal.
Step 4Fold the tamale: Fold the lower, then upper thirds of the tamale lengthwise over the center and filling, then fold the two sides in to form a packet. Repeat with all of the tamales.
Step 5Steam the tamales until the masa in the center is fully cooked (it will peel away from the banana leaves without sticking), about one hour. Serve hot.