In a small bowl, mix warm water, sugar, and yeast. Let it sit for 10-15 minutes until the mixture starts to foam.
In a large bowl, mix flour and salt. Create a well in the center and add the yeast mixture, yogurt, and oil/butter. Mix and knead for about 5-7 minutes until you get a smooth and elastic dough. The dough should be slightly sticky.
Brush the dough with a little oil, cover with a towel, and let it rise in a warm place for 1.5 to 2 hours until it doubles in size.
Divide the risen dough into 8 equal parts. On a lightly floured surface, roll each part into an oval or teardrop shape about 15-20 cm long.
Heat a heavy skillet (ideally cast iron) over high heat. Place one naan on the hot skillet and bake for about 1 minute until bubbles appear on the surface.
Flip the naan and bake the other side for another 1-2 minutes until dark spots appear and the naan is cooked through. For an authentic, fluffy finish, you can hold the naan with tongs directly over a gas burner flame for a few seconds.
Brush the baked Naan immediately with melted butter. For garlic naan, mix minced garlic with the butter. Serve warm.