Mix the two flours and the yeast and salt thoroughly in a bowl if making by hand, or in the bowl of a stand mixer.
Add the oil and yogurt and knead for about 10 minutes, using low speed if using a stand-mixer, to form a smooth dough. Add water if necessary.
Place the dough in an oiled bowl and turn it over once to coat all sides.
Let it rise about 2-3 hours in a warm place.
Divide the dough into six balls. Let them stand around 10 minutes. Then, roll each ball into an oval, about 6-7 inches in diameter at the longest point. Make sure you roll out the naan evenly and don't roll it out too thin, to ensure it puffs up in the oven.
Brush with oil and sprinkle some sesame seeds on top of each oval.
Preheat an oven to 475 degrees, placing a pizza or baking stone on the middle rack. I just use four unglazed clay tiles that I bought long ago from a hardware store and they do the job just as well.
Place as many naans as possible on the stone without overlapping. I just bake two at a time.
Bake about five minutes. The bread will puff up and light brown spots will appear on the top when it's done.
Serve hot with the bharta.