Preheat a griddle to 350 degrees F.
In a large mixing bowl, combine the flour, salt and baking powder.
Next, add in the shortening.
Using your hands, work the shortening into the flour mixture by flattening the small chunks of shortening between your thumb and forefingers. Continue doing this until all the shortening has been completely incorporated into the flour mixture. It will look crumbly in appearance when done.
Slowly, 1 cup at a time, add warm water while kneading and working the water into the flour to make a dough. The dough should be slightly sticky so you might need to adjust the amount of water accordingly.
On a floured surface, split the dough into small pieces about the size of your palm.
Roll out the pieces of dough using a rolling pin until the tortillas reach the desired size. I usually try to make my tortillas about 12".
Transfer the uncooked tortillas to griddle.
Cook each side for 1-2 minutes until the tortillas are cooked through and slightly browned. Be careful not to overcook or the tortillas will be crunchy and will not fold well. Repeat this process until all the dough has been cooked.