How to Make It
In a glass measuring cup, combine the yeast, sugar, and water and let sit for 10 minutes. In the meantime, mix the flour, baking soda, and baking powder in a large bowl.
Whisk together the yeast mixture, yogurt, and milk and stir into the dry ingredients. Knead with your hands until the dough forms a smooth, soft ball, about 2 minutes. Place the dough in an oiled bowl and cover with plastic wrap. Leave at room temperature until doubled in size, about 2 hours.
Preheat oven to 400º. Slice the chiles, toss with oil, and place in a single layer on a baking sheet. Roast for 10 minutes, until soft and slightly browned. Set aside.
Remove the dough from the bowl and turn onto a well-floured surface. Knead briefly and divide dough into 12 equal portions. Roll into 1/4 inch thick ovals, approximately 6 inches wide.
Heat a cast-iron skillet over moderately high heat. Sprinkle each portion with roasted chiles, brush with melted butter, and then place it in skillet. Cook for about one minute, until the dough puffs up. Flip, cover the pan, and cook for one more minute. Remove from the pan and brush both sides with butter and sprinkle with salt. Place in a towel-lined bowl until ready to serve.