In a bowl or the bowl of a food processor fitted with the steel blade, place the almond flour, coconut flour, xanthan gum, baking powder, and salt. Whisk or pulse to combine.
Add the beaten egg and 2 tablespoons of water. Pulse or mix to combine.
If the dough holds together well and feels moist but not wet, mix or process until it forms a cohesive dough. If using a food processor, process just until it forms a ball and mostly clears the dough from the bottom of the container.
If the dough feels at all dry, knead or process in more water by the quarter teaspoonful until it reaches the proper consistency.
Let the dough rest
Transfer the dough from the bowl or food processor to a piece of plastic wrap, wrap tightly and store in the refrigerator until you’re ready to make the tortillas (up to 7 days). It’s best to allow the dough to chill for at least 10 minutes.
Shape the tortillas
Unwrap the chilled dough, knead in some of the optional tapioca starch to smooth out the dough, and roll it out into a rough rectangle. Fold it in thirds like a business letter, then fold in the sides to form a packet.
Using a bench scraper or sharp knife, divide the packet it into 8 pieces of equal size. Roll each between your palms into a smooth ball. Remove about 1/4 of one ball and add it to another, and begin working with the larger piece of dough.
Press the first piece of dough into a disk and place in on a large, clean surface. Use a rolling pin to roll the dough into a round about 7-inches in diameter, dusting lightly with the optional tapioca starch to prevent sticking as you work.
In place of tapioca starch to prevent sticking, you can roll each piece of dough into a round between two sheets of parchment paper or plastic wrap.
Use the cake cutter or pot lid to cut out a 6-inch round. Remove the excess dough trimmings and add them to the next piece of dough, the one from which you had removed 1/4.
Repeat the process with the next piece of dough, transferring excess to the one after it. Sprinkle the raw tortillas lightly with tapioca starch to prevent them from sticking to each other.
Cook them
When you’re ready to make the tortillas, heat a nonstick or cast iron griddle over medium-high heat for at least 5 minutes. If using an electric griddle with a temperature gauge, heat it to 375°F.
Place the shaped, raw tortilla on the skillet or hot griddle and press down with a wide, flat spatula. Allow to cook until bubbles start to form (about 20 seconds), then flip and press down until the tortilla looks opaque on both sides and is browned in spots. Flip again to brown more on the first side.
Repeat with the remaining dough, stacking the warm tortillas on top of one another.
Storage
Serve immediately, or place a stack of cooked tortillas in a zip-top plastic bag or tortilla warmer with a lid. Place a moistened paper towel into the bag before sealing it tightly. This will help keep them moist and pliable.
They can be refreshed in a hot, dry skillet before serving if desired.
Video
Notes
About almond flour Be sure you're using finely ground and sifted blanched almond flour with its skins removed, not almond meal, which has its skins intact and is more coarsely ground. About coconut flour In place of coconut flour, you can use 6 tablespoons (48 g) of tapioca starch/flour. The tortilla dough is a bit more fragile and the tortillas a bit less flexible, but the recipe still works. About xanthan gum You can use an equal amount of guar gum or konjac powder, or 8 grams finely ground blonde psyllium husk powder, in its place for a similar, although not exact, results. Adapted from Farm To Jar.