In a medium sized bowl, whisk together flour and salt. Cut in the butter using a fork or your hands until it is well incorporated. 

 Next, add in the water and sourdough starter and mix until a shaggy dough forms. 

 Flour a countertop and turn out the dough onto the floured surface. Knead with hands for a few minutes until the dough is smooth and not sticking 

 Cover the dough and allow it to rest at room temp. for 30 minutes to an hour.

 Cut the dough into 12 equal pieces and roll into balls. 

 Using a tortilla press or a floured surface and rolling pin, roll the dough as thinly as possible. Until they are almost see-through.

 Heat a cast iron skillet over medium heat. 

 Cook each tortilla for several minutes on each side. 

 Serve immediately or cool and store in an airtight container in the fridge for 4-5 days.