Combine flour, salt, and baking powder in a medium bowl. Add the lard and vegetable shortening and rub it in with your fingers. Add 1 1/2 cups lukewarm water and knead for 2-3 minutes until a smooth dough has formed. Cover with a clean dish towel and let rest 15 minutes.
Heat a cast iron skillet or comal over medium heat. Remove golf ball-sized pieces of dough and roll out on a lightly floured surface until they are as thin as possible (about 1/8-inch thick).
As you are rolling cook each tortilla on the hot, dry skillet until toasted on both sides, about 1 minute per side. Keep warm in a clean towel and repeat with remaining dough.