In a saute pan, heat the olive oil. When the oil is hot, add the chorizo and saute for 2 minutes. Add the onions and continue to saute for 1 minute. Remove from the heat and add garlic. Season with salt and pepper. In an electric mixer, mix the shortening until light and fluffy. In a mixing bowl, combine all the dry ingredients together. Gradually stir in the stock and form a soft dough. With the mixer on medium, slowly add the dough mixture into the shortening, the mixture will be sticky. Drain the corn husks and pat dry. Tear 12 strips 1/6-inch wide from 2 of the husks for tying the tamales. Place 2 husks together with the large ends overlapping by 2 inches. Repeat for the remaining husks. Divide the tamale dough evenly between the husks and spread in the center, leaving 1-inch at each end uncovered. Place the chorizo mixture on top of the dough and roll the corn husks so that the filling is completely enclosed. Twist and tie each end with the 1/6 inch strips already torn off. Steam the tamales in a vegetable basket set in a saucepan with water and covered with a tightfitting lid. Steam for 30 to 35 minutes. The tamales are done when the dough comes away from the sides. Remove the tamales and serve with the mole sauce.