In a small bowl, combine the active dry yeast, sugar, and warm water. Stir gently and let it sit for about 5-10 minutes, or until the mixture becomes frothy.
In the bowl of your stand mixer, combine the flour and salt. Add the yogurt and olive oil, and then pour in the yeast mixture. Attach the dough hook to your stand mixer. Mix on low speed until a dough forms. Increase the mixer speed to medium and knead for 5-7 minutes, until the dough is smooth and elastic.
Place the dough in a lightly oiled bowl, cover with a damp cloth, and let it rise in a warm place for about 1 hour, or until it doubles in size.
Once the dough has risen, punch it down to release the air. Divide the dough into 8 equal pieces and roll each piece into a ball.
On a lightly floured surface, roll out each ball of dough into an oval or round shape, about ¼ inch thick.
Heat a large skillet or griddle over medium-high heat. Once hot, place a rolled-out dough onto the skillet. Cook for about 1-2 minutes, until bubbles form on the surface and the bottom is golden brown. Flip and cook the other side for another 1-2 minutes. Repeat with the remaining dough pieces.
Brush the cooked naan with melted butter and garnish with chopped fresh cilantro if desired. Serve warm.