In a stand mixer with a dough hook (or by hand), combine the sourdough starter, water, melted butter, salt, and flour. Knead for 3 minutes in the mixer, or about 6 minutes by hand, until the dough is smooth and slightly elastic. You made need to add a little more flour depending on the thickness of your starter or if using sourdough discard.

Transfer the dough to a greased bowl that is not metal, cover with a damp tea towel, beeswax wrap, or plastic wrap, and let it rest at room temperature for 12-24 hours. You can also use this dough right away without a long rest period! See notes for details.

The next day, divide the dough into 12 equal portions and shape each one into a ball.

On a lightly floured surface, roll each dough ball into a thin circle, about 1/4 inch thick. Try to make the tortillas as thin as you can without tearing the dough.

Preheat a cast iron skillet over medium heat. Cook each tortilla for about 1 minute on each side, until they puff up and develop light golden spots.

Cover the cooked tortilla with a clean dish towel while cooking the others to keep it warm and the little bit of steam they make keeps them soft.

These tortillas are best enjoyed warm, but they can be reheated in a skillet or oven. Use them for tacos, wraps, or as a flatbread base for your favorite toppings!