From: Art of Gluten-Free Baking (http://artofglutenfreebaking.com)
Yield: about 9- 7 inch/18 cm tortillas
In the bowl of a food processor, place the flour, salt, and baking powder. Pulse a few times to mix.
Add the butter pieces. Pulse until the mixture looks like wet sand. Add the warm water and turn on processor until a dough ball forms. The dough should be soft and pillowy.
Turn out dough onto a piece of plastic wrap and wrap tightly. Let sit at room temperature for 1 hour. This rest period will help to distribute the water throughout the dough. If you don’t plan on using the dough that day, you can refrigerate the wrapped dough. But will need to bring it to cool room temperature before you roll and make the tortillas. Please note that if the dough is too warm, it will be hard to roll and it will be too floppy to move to the pan. It’s best when it’s on the cooler side of room temperature.
When you are ready to make the tortillas, roll your dough into 9 equal balls of about 1/4 cup/65 grams each. Cover the balls with plastic wrap while you preheat your pan.
The tortillas need to be cooked in a pan that can be heated to a high temperature. I use a well-seasoned cast iron pan for this. Place pan on medium high heat and let preheat well–for about 5 minutes. If you have a tortilla press, now is the time to use it. Dust the press with tapioca flour (top and bottom). In addition, dust rolling surface with tapioca flour.
Place the first dough ball in the middle of the press and firmly press. Open the press. Most likely the disk (which should be about 5 inches/13 cm in diameter) will stick to the upper part of the press (as it does for me).
Carefully remove the dough disk and place it on the floured rolling surface. Sprinkle the surface of the dough disk with tapioca flour. If you don’t have a tortilla press, proceed to the next step.
With a rolling pin give the dough disk (or dough ball if you didn’t use a tortilla press) a roll. Give the disk a quarter turn and roll it again. Repeat this process until you have a disk that is roughly 7 inches (18 cm) in diameter. Don’t roll these any thinner.
If the dough gets too thin it will be almost impossible to transfer from the rolling surface to the pan. If the ragged edges bother you, you can cut them off at this stage with a sharp knife.
With a large turner, carefully transfer the dough disk to the heated pan. It might take you a few tries before you are able to transfer the dough disk without it breaking. If your kitchen is hot, the dough might get too warm and might get floppy and be harder to roll and to transfer. If this happens, put dough into the fridge to cool down and firm up.
Cook for about 60 seconds–until the surface of the tortilla is covered with puffed up bubbles.
Flip and cook on the other side for another 60ish seconds. Both sides should look like they do in the photo–with brown rings where the bubbles have formed.
Flip the tortilla onto a dinner plate hot side up. You will now repeat the process with each dough ball. Flip each successive tortilla hot side up onto the tortilla stack. By the end of the process, you will have 9 tortillas. Cover warm tortillas with a towel to keep warm and serve.
Tortillas are best fresh–they will be pliable and should roll around a filling fairly easily.
Cool completely and then store in an airtight container at room temperature (not in the fridge) for up to 5 day. For longer storage, freeze. To refresh, microwave for a few seconds before use.