Combine flour, salt, and instant yeast in a bowl. Make a well in the middle, pour in the yogurt and oil, and combine.
Slowly mix in the milk until all the dry flour is incorporated.
Knead the dough for 5 minutes, then form it into a ball. Rub a small amount of oil around it and cover the bowl—letting it rise for 1½ hours.
On a lightly floured work surface, divide the dough into 8 portions, and form each into a small, taut round. Dust the tops with flour and cover. Let them rest for another 30 minutes.
Heat a well-seasoned cast iron skillet (at least 10" in diameter) on high heat.
Roll out one of the balls until it is about a ¼" thick. Dust with a small amount of flour if it's sticking to the surface or the rolling pin.
Gently slap the rolled out dough onto the hot cast-iron. It should form bubbles in about 30 seconds. Flip it when the spots have reached a really dark brown (or even black) and cook for about another 30 seconds. Repeat this process with the remaining dough rounds.