First you’ll need to roast the chile in order to peel the tough skin. Place the chile under the broiler until blackened, about 5 minutes per side. Place chile in a paper sack or plastic food-storage bag, close it tight and let the chile steam for 20 minutes. Take the chile out of the bag and rub off the skin. Remove stem and seeds and dice the chile.
To make the tortillas, in a medium bowl stir together the flour, baking powder, and salt until well combined. Stir in the diced chile until well distributed. Pour in the oil and warm water, and stir until a soft dough is formed (if it feels too wet, you can a more flour, a tablespoon at a time.) Cover the dough and let it rest for 1 hour.
After an hour, divide the dough into 8 balls. Lightly flour a clean surface and one at a time place a dough ball on the floured surface, pat it out into a 4-inch circle, and then roll with a rolling pin from the center until it’s thin and about 8 inches in diameter. If the chile peppers fall out of the dough as you roll, pick them up and then lightly press them in the center of the tortilla, flip the tortilla, and then continue rolling.
Keep the rolled-out tortillas covered until ready to cook.
In a dry cast-iron skillet heated on medium high, cook for 30 seconds on one side, flip it and then cook for 1 minute on the other side. It should start to puff a bit. Flip it again and cook for 30 seconds more. Place cooked tortillas in a basket lined with cloth or a tortilla warmer. Repeat process for remaining balls of dough.