Mix warm water, sugar, and yeast; let sit until foamy
In a bowl, combine flour, salt, and baking powder
Add yogurt, oil, and the yeast mixture
Mix until a dough forms
Knead the dough until smooth and elastic
Cover and let the dough rise until doubled in size
Divide the dough into equal portions
Roll each portion into an oval or round shape
Heat a skillet, griddle, or tandoor until very hot
Cook each naan on one side until bubbles form
Flip and cook the other side until browned
Brush with melted butter or ghee
Serve warm