In a food processor combine 2 3/4 cups of the flour (reserve the remaining flour for rolling out the dough) with the lard or shortening. Pulse several times until the fat is evenly distributed throughout the flour and no particles of fat are visible. Dissolve the salt in 2/3 cup of the warm water. With the machine running, pour the liquid through the feed tube in a steady stream and stop the machine once the dough has come together in a ball. Feel the dough, it should be a medium-stiff consistency, not too firm but not as soft as most bread doughs. If the dough is too stiff, divide it into several pieces, sprinkle with 1 or 2 tablespoons of the remaining water and process again until a ball forms.
Divide the dough into 12 portions, roll into balls and place on a flat surface or plate. Cover with plastic wrap and allow dough to rest for at least 30 minutes.
On a lightly floured surface roll each ball into a 7-inch circle by flattening the ball of dough, lightly flouring it, and with a rolling pin rolling forward and backward over the dough, then turn it a sixth of a turn and roll forward and backward again. Repeat the turning and rolling process until a 7-inch circle is formed, re-flouring the work surface as necessary. Place the tortilla on a plate and cover with plastic wrap. Repeat the rolling out process for the remaining 11 balls of dough.
Heat a flat cast iron griddle over moderately high heat. Lay a tortilla on the griddle and cook for 20 to 45 seconds until tortilla bubbles and lightly browns on the underside. Flip the tortilla and cook it for another 30 to 45 seconds. The tortilla should be lightly browned but still soft and flexible. Transfer the cooked tortilla to a heavy towel and wrap it up. Cook the remaining tortillas in a similar manner and store stacked in the towel to keep them warm and soft.
The tortillas can be stored in a sealable plastic bag and refrigerated until ready for use. To reheat the tortillas, tuck them in an "envelope" made out of aluminum foil and heat in a 325 degree oven for 10 to 15 minutes.
Adapted from a recipe by Rick Bayless, Authentic Mexican