In a large bowl, whisk together the flour, masa harina, salt, and baking powder. Add the coconut oil and stir with a flexible spatula or your hands until evenly distributed. Add the water, stir to combine, and work the dough with your hands or a bowl scraper until homogenous and Play Doh-like in consistency; it shouldn’t crack when squeezed.

Divide the dough into 6 equal pieces (about 73g each) and roll them into balls. Place on a lightly greased plate or baking sheet, cover, and let them rest for 30 minutes.

Heat a cast iron skillet over medium-high heat.

Working with one ball of dough at a time, transfer the dough to a floured surface. Lightly flour the surface of the ball, then flatten it into a disk. Roll it into a 3" to 4" circle, then transfer to a square of parchment at least 5" big or an 8" parchment round. Continue to roll, on the parchment, until you reach a 7" to 8" circle, adding flour as needed. (Rolling on parchment makes the transfer to the pan seamless.) Roll out a second ball using the same method.

With the help of the parchment, invert one tortilla into the hot pan and peel away the parchment. Cook for 1 to 2 minutes, until puffy, with lots of browning on the bottom. Flip, press down firmly with a spatula for about 10 seconds (this encourages more puffing), and cook for another 1 to 2 minutes, until the dough doesn’t appear raw and is nicely charred on both sides. Adjust the heat as necessary if the tortilla is browning too quickly. Wrap the cooked tortilla in a clean, lint-free kitchen towel so that it stays warm and soft while you make the others.

While the first tortilla cooks, roll out another (since you started by rolling out 2, you’ll always be one ahead of what you need!). Continue to cook and roll, reusing the original 2 parchment pieces, until all the corn and flour tortillas are cooked. Serve warm.

Cool and leftover corn and flour tortillas, and store in an airtight container at room temperature for up to 3 days. For very pliable tortillas, microwave very briefly (about 10 seconds); otherwise, reheat on the stovetop.