Feed your sourdough starter the night before you want to make these so it is active and bubbly in the morning.
Combine hot water and milk in a large mixing bowl or the bowl of a stand mixer fitted with the dough hook.
Continue to add the active sourdough starter and salt. Mix well.
Add the flour about a cup at a time and knead for about 5 to 8 minutes until you have a dry, not sticky, dough.
Place the dough in a non-metal bowl and cover it with a damp tea towel, beeswax wrap, or plastic wrap. Set in a warm place to rise for 6 to 8 hours.
When ready to bake, preheat your oven with the baking stone in it to 500 degrees F for at least 30 minutes.
Take the dough and use a bench scraper or a knife to divide it into 12 equal pieces. Set the pieces on a cookie sheet and cover them with a damp tea towel. They will continue to rise a little as they rest.
When ready to bake, Take a piece of dough and roll it out into an oval about 6 inches across. Dust a pizza peel or cookie sheet with flour and set the flattened dough on it.
Quickly open the oven door and slide the dough onto the baking stone. I can fit 2 on my baking stone.
Watch closely for the pita to puff up into a ball. This only takes 3 or 4 minutes. Do not let it brown! If it starts to brown before fully puffing up, remove it from the oven.
Once it has puffed up, quickly remove it from the oven, place it on a plate and cover it with a clean kitchen towel.
Continue until all of the pitas are cooked. If as you cook more pitas they aren't puffing up as well, take a break and allow your oven to heat back up for 5 or 10 minutes then resume cooking.
To enjoy, cut a pita in half and then gently use your finger or a knife to separate the two sides and open the pocket up. Be careful as steam will come out!
Fill with your favorite sandwich ingredients and enjoy!