In a large bowl, place the flour, xanthan gum, tapioca starch/flour, salt, and baking powder, and whisk to combine well.
Add the oil and milk, and mix to combine. The mixture will seem very wet at first, but the flour will begin to absorb the liquid quickly and the dough will become stiffer.
If the dough doesn’t come together, knead it briefly with clean hands until smooth.
Ideally, divide the dough into 5 ounce portions (as written, the dough makes 2 portions), wrap each tightly in plastic wrap, and chill for 30 minutes and up to 3 days. You can also work with the dough immediately, if you don’t have time to chill it.
Shape and cook the bread
Heat a cast iron skillet that’s at least 10-inches in diameter, or a heavy-bottom nonstick skillet, over medium heat. Place a flat, wide spatula and a tea towel on the counter next to the skillet.
If you’ve chilled the dough in portions, unwrap and work with one piece at a time. If the dough hasn’t been divided, divide it in two equal halves, each weighing about 5 ounces.
Turn each piece of dough out onto a very lightly floured flat surface, and sprinkle lightly with extra flour. Cover the remaining dough loosely with a cloth to keep it from drying out.
Sprinkle the dough lightly with more flour and begin to roll it into a round, sprinkling lightly with more flour as necessary to prevent sticking. The edges will be jagged and a bit rough.
Gather the dough together and repeat the process at least once more, until the dough is smoother. Roll the dough into an approximately 8-inch round, turning and flouring lightly as necessary. The edges should be less rough, but this is rustic flatbread.
Brush about 1 teaspoon of neutral oil on the hot skillet. Pick up the prepared raw piece of flatbread and place it flat in the center of the skillet, taking care not to bend any of the edges.
Allow it to cook for about 1 minute without disturbing it, or until the edges begin to lift. Slide the spatula underneath the flatbread, ensuring that there are no spots that are sticking.
Flip the flatbread over and allow it to cook for another minute, pressing it firmly back onto the skillet with the spatula to prevent it from puffing up. You can also take a toothpick and prick any bubbles to deflate them.
Continue to cook the flatbread, flipping it frequently, until it is set on both sides and doesn’t glisten anywhere. It should take 2 to 3 minutes total.
Remove the flatbread from the skillet, place it in the center of the tea towel, and fold the edges of the towel over on it to enclose it and keep it warm.
Repeat with the second piece of dough, adding more oil to the skillet if needed.
To roll the flatbread
If you'd like to roll them in a coil while they are still very warm, open the tea towel and remove both pieces of bread. Place one about 4 inches from one short end of the towel, fold the edge over the bread, and roll the bread tightly in the towel.
Place the second flatbread on the unrolled portion of the towel, and repeat the process, rolling until the two flatbreads are tightly wrapped in the towel. Allow them to cool for at least 5 minutes wrapped in the towel before unwrapping and serving.
Video
Notes
Flour blend choicesMy favorite gluten free flour blends are Better Batter's original blend gluten free flour and Nicole's Best multipurpose blend (with 1/2 teaspoon added xanthan gum). King Arthur Flour's gluten free bread flour may also work here, but the dough might be more stiff and the bread less flexible.Bob's Red Mill 1-to-1 Gluten Free Baking Flour should also work here, but I recommend adding an extra 1/4 teaspoon xanthan gum to the dry ingredients for a more stable dough and bread.I don't recommend Cup4Cup any more, especially for bread baking. To make your own blend using one of my “mock” recipes, please see the all purpose gluten free flour blends page.Tapioca starch/flourYou must use tapioca starch (or flour, they’re the same thing) in this recipe in addition to a proper all purpose gluten free flour blend. You cannot use Expandex modified tapioca starch. They’re completely different ingredients.Rolling in a tea towel.Rolling the warm flatbreads in a tea towel is optional, but it helps them hold their shape and stay flexible as they cool. They’re very bendy either way.Adapted from Curious Cuisiniere.