In a large skillet, heat oil over medium heat. Add onion, tomatillos, garlic and jalapeno and sauté for 3 – 4 minutes. Add chile powder, cumin, salt and turkey breast and stir to blend flavors. Simmer for 2 – 3 minutes and then allow to cool.

For each tamale, lay the corn husk on a flat surface with the narrow end pointing towards you. Take about 2 – 3 tablespoons of the masa and spread evenly along the bottom quarter of the corn husk, about 1/2 inch from any edge of the husk. In the center of the masa, place a few tablespoons of the turkey mixture. Fold the left edge over the stuffing. The idea is to surround the stuffing with masa. Fold the right edge over and fold the bottom up towards the center. Place in a hot steamer basket with a water level just under the bottom of the basket. Place tamales fold-side-down in basket, leaving a little room between each so that steam can cook each one. Add water as they steam, if necessary. Tamales will take from 25 – 40 minutes to steam, depending on how big they are. They will be soft, moist and hot when cooked and will firm up as they start to cool.