In the bowl of a stand mixer, place the all purpose flour, whole wheat flour, baking powder, salt and sugar. Mix until combined.
To the dry ingredients, add the oil, water and milk. Using the dough hook of your stand mixer, mix and knead the dough for about 7 to 10 minutes until the dough comes together and is not sticky anymore. The dough should be soft and not hard at all. If it feels hard, add one to two tablespoons of water and knead again.
Cover the bowl with a kitchen towel and let it sit for 20 minutes.
Transfer the dough to a lightly floured surface and divide it into 8 pieces. Shape each piece to a ball and roll it out gently with a rolling pin into a disk with ¼ inch thickness.
Heat a cast iron skillet (or a non stick skillet) over medium heat.
Once the skillet is hot, brush the naan on top with melted ghee. Transfer the naan to the skillet, ghee side down and cook for about 30 seconds until it's golden and has bubbles. Brush the top with ghee and flip so it cooks on the other side as well. This should take about 30 seconds or less.
Once the naan is cooked, transfer to a plate and cover with a kitchen towel so it stays soft. Continue with the remaining dough.
Serve with your favorite main dish.