In a large bowl, whisk together the flour, sugar, salt, and active dry yeast.
Stir in the warm milk and water, using a silicone spatula, until just combined.
Using (floured) hands, knead the dough until it forms a smooth ball.
Cover the dough ball in olive oil, then place it back into the bowl and cover with a clean kitchen towel. Let the dough rest for 1 hour.
After an hour, punch down the dough.
Slightly roll out the dough into a thick circle, and then cut into 8 even-sized pieces.
Stretch out a piece of dough with your hands, then fold each "corner" back into the middle. Finally, roll the piece into a smooth ball. Repeat with the remaining pieces of dough. Let the dough balls rest, covered with a towel, in your mixing bowl for 10 more minutes.
Heat a cast-iron skillet to medium-high heat.
Take a ball of dough and roll it out into a thin, circular shape. Add extra flour to avoid sticking if needed.The disc should be really thin and almost see-through. They will shrink slightly in size when cooking. Cook the dough disc on a plain cast-iron skillet, about 30 seconds on each side. Flip after you see large bubbles form on the dough.
Repeat steps 10 - 11 until all of the naan dough is cooked. Set aside.