For even mixing, sift flour, baking powder and soda together in a large bowl. Create a small well in the center of dry mixture. Add salt, sugar, curd and ghee in the well. Mix well using your hands or wooden spoon.
Allow it to rest for couple of minutes.
Using your fingertips, knead the dough into a firm dough ball while adding lukewarm water 1 tablespoon at a time. Knead for 5-6 minutes. Form a smooth ball and allow it to rest covered with a cling film in a warm corner for 4-5 hours.
When ready to cook, If you have a tandoor preheat it or heat up a tawa. Break the dough into smaller dough balls. Press the dough ball into a small disc, sprinkle nigella seeds on it.
Roll out the dough into tear shaped naan. The seeds will now stick well to the naan. Apply little water on top of the naan using your fingers or a pastry brush.
Place it on the hot tawa with wet side down on tawa. Cook on medium flame, the naan will puff up, now flip over the tawa allowing the naan to directly cook on the flame from other side, still sticking to tawa from one side.
If you are using a tandoor, then stick the naan on the dome lid of the tandoor and allow it to puff. Then gently scrape it off the lid and allow it to cook on the wire rack of the tandoor from the other side.
Apply ghee or butter while serving. Serve hot with some delectable main dish.