Soledad's Tamal Oaxaqueno de Mole con Pollo

Directions

1. Place chicken, garlic, and peppercorns in a medium stockpot. Add enough water to cover by 2 inches. Bring to a boil. Reduce heat, and simmer until cooked through, 35 to 45 minutes. Strain through a fine mesh sieve, reserving liquid. Let chicken stand until cool enough to handle. Remove meat, and shred into bite-size pieces; set aside. Discard skin and bones.
2. If banana leaves are thick and not supple, they need to be steamed: Pour a couple of inches of water in a large pot, and bring to a boil, then reduce to a simmer. Roll banana leaves loosely, and arrange in a steamer basket. Place basket over water, cover, and steam leaves until pliable, about 30 minutes.
3. In the bowl of an electric mixer fitted with the paddle attachment, combine masa, 1/2 cup reserved chicken-cooking liquid (freeze remaining liquid for another use), salt, and shortening, and beat on medium until light and fluffy, 3 to 5 minutes; set aside
4. Place a 12-inch piece of banana leaf on a flat work surface (if leaves are smaller, you can use a few to create one larger surface). Spread a very thin layer of the masa mixture (about 1/4 inch thick) over the banana leaf, leaving a 1-inch border. Place 1/2 cup of shredded chicken in center of the masa. Pour 1/4 cup mole over chicken. Fold edges up and over to enclose filling and form a packet. Repeat with remaining leaves, masa, chicken, and mole (reserve 1 1/2 cups mole for serving).
5. Bring a pot of water to a boil, then reduce to a simmer. Arrange masa packets in steamer. Place over water, cover, and steam for 1 hour.
6. To serve, use a serrated knife to cut a cross in the center of the package. Pull back corners, exposing tamale. Drizzle with remaining mole, and sprinkle with sesame seeds.