Add the sourdough starter and hot water to the stand mixer bowl and mix until the sourdough incorporates.

Stir in the butter.

Add the remaining ingredients to the bowl.

Using a dough hook, mix all ingredients on speed 2 for 5 minutes, or until the dough forms a smooth ball.

Cover the dough and let it rest for 1 hour.

Dump the dough out onto a clean work surface and cut into 10 equal portions. Roll each portion into a ball.

Cover the dough and let rest for 30 minutes.

Keeping the dough that is not currently being worked with covered, roll out each portion one by one with a rolling pin. Use flour sparingly, but as necessary. Once the dough is as thin as you can roll it without it tearing, sprinkle it with flour and cover it with a clean towel or plastic wrap. Roll out the remaining portions of dough, covering each when you're finished working with it.

Let the tortillas rest for 20 minutes.

Preheat a large skillet or griddle to medium-high heat.

Work with one tortilla at a time while keeping the rest covered. Place a tortilla on a lightly floured work surface.

Roll the edges with a rolling pin, rotating the tortilla so that you roll all sides until the tortilla has reached the desired thinness.

Place the tortilla on the preheated skillet or griddle. Cook for 1 minute, then flip and cook for another minute on the other side. The tortilla should have small golden marks on both sides. Transfer the tortilla to a clean plate and cover with a clean towel.

Repeat last 2 steps until finished. Serve the tortillas warm.