In a large bowl, stir together the masa harina, salt and hot water. Gradually mix in the shortening and flour. If the dough seems dry, add a little more hot water. Form the dough into balls that will fit into the palm of your hand. Line a work surface with waxed paper or plastic. Sprinkle with water. Flatten balls on the wet surface until about 1/4-inch thick. Heat a griddle or comal over medium heat. Cook the gorditas on each side until they are cooked through. Heat oil in a large heavy skillet over medium to medium-high heat until hot. Fry each gordita until puffed, pressing it down into the oil occasionally with a spatula. Drain briefly on paper towels, cut the tips off and stuff full of your favorite foods.