Sift the flour, cornshtarch, and salt together, then put on a clean, smooth working surface and make a well in the center. Put the soft lard, shortening, and butter, together with the water, eggs, and egg yolks, into the well and work them togehter with your fingers until you have a smooth emulsion. Gradually work in the flour and knead the dough well until it is soft and smooth. Divide the dough into three equal balls about 10 ounces each. Brush them liberally with melted lard, cover with a towel and set them aside (not in the refrigerator) for at least 2 to 3 hours. One by one, flatten each of the balls and roll them into 9 x 9 inch squares about 1/4 inch thick. Brush the surfaces liberally with melted lard, sprinkle with flour, and put one on top of the other. Roll them out to make one slightly bigger square, about 11 x 11 inches. Carefully roll the three layers together, not too tightly but not too loosely, into a sausage shape about 11/2 inches in diameter. Brush the roll with plenty of melted lard and set aside for another 2 hours. Meanwhile, prepare the filling. Heat the oil and fry the onion, chiles, and tomato together until they are well cooked and have a sauce like texture. Stir in the vegetables and chicken, season, and let the mixture cool off thoroughly before filling the Empanadas. Preheat the oven to 425 degrees. Cut the roll into rounds about 1/2 inch thick and roll each one out into a circle about 4 inches across. Put about a heaped tablespoon of the filling onto one side of the dough, then fold the other side over to cover the filling. Pinch the semicircular edges together firmly, twisting with your fingers to form little scallops around the edge. Place the empanadas well apart on an ungreased baking sheet and bake for about 25 minutes, until well browned. Sprinkle with the sugar and serve immediately, as a light supper dish or hors doeuvre. Notes: Empanadas de San Cristobal de las Casas If you are ambitious and/or desire a very portable meal, try the savory chicken pastries, Empanadas de San Cristobal de las Casas. [Makes 2 dozen pastries] Recipe by: Mexican Regional Cooking by Diana Kennedy Recipe by "Pillsbury Kitchens Family Cookbook" 1979 edition Posted to MC-Recipe Digest by KitPATh on Feb 17, 1998