Combine yeast, sugar, and water in a small bowl. Set aside and let bloom for 5 minutes.
Sift together the flour, salt, and baking powder in a large bowl.
Mix the yeast mixture into the dry ingredients, followed by the oil, milk, and yogurt. Knead, folding as you go, until it is soft and pliable.
Cover dough and let rest in a warm location.
Punch down dough and divide into even balls. Roll each ball into a 1/4"-thick naan.
Heat a tawa over medium heat. Working one at a time, lightly wet the bottom of the naan and place it in the hot pan. Cook until puffed up and browned.
Invert the pan over the heat source, taking care not to dislodge the naan. Cook until the top of the naan is dark brown in spots. Alternatively, just flip the naan and cook the other side in the pan until dark brown.
Despite previous success with this recipe, I think additional sources of this recipe need to be evaluated and this one updated.
Made a double without yogurt (sub'ed with milk). The dough was very dry and stiff, making it hard to work with by hand, but after a while it did become smooth an elastic as desired. The naan made with this were quite good, both crisp and soft, and puffed up pretty well.
Made a double, and again the dough was very dry. I had to add probably nearly 1/2 c. water to get this to a workable consistency. I divided the dough into 8 portions but I think dividing smaller would give better results, as the naan will be thinner and crisper. I cooked these on cast iron, first placing the dough disk on the hot surface, then adding a splash of water and covering with a lid until the first side is beginning to blacken in spots. Then I flip and continue cooking with the lid off until blackened in spots on the second side. I think that having the naan covered to start may help it rise more, but it also causes the surface starch to gelatinize and get slightly shiny, reminiscent of bagels/pretzels. Not unpleasant, but not why I expect from naan. I think possibly adding less water or not keeping covered as long will yield better results.