In a mixing bowl, combine warm water, sugar, and yeast. Let it sit for about 10 minutes until foamy.
In another bowl, mix the all-purpose flour and salt. Gradually add the yeast mixture, yogurt, and olive oil, and knead until a smooth dough forms.
Cover the bowl with a clean kitchen towel and let the dough rise in a warm place for 1 hour or until it doubles in size.
Once the dough has risen, punch it down and divide it into four equal balls.
In a separate bowl, combine the mozzarella cheese, feta cheese, garlic powder, and cilantro.
Take one dough ball and roll it out on a floured surface into a round shape, about 1/4 inch thick.
Place a generous amount of cheese filling in the center. Fold the edges over to seal the filling inside and gently flatten the ball again.
Heat a skillet or baking sheet over medium-high heat. Cook the naan bread for about 3-4 minutes on each side until golden brown and cooked through.
Brush the cooked naan with melted butter before serving.