Dissolve the yeast in half a cup of warm water and let stand for 10 minutes.
Mix the ghee and sugar into the flour. Add the yogurt and the yeast mixture (or the baking soda), plus a little more warm water if needed. Knead well into a soft, elastic dough; a little oil can help with kneading.
Cover with a damp cloth and set aside for 4 hours.
Heat the ghee in a frying pan.
Divide the dough into small balls and roll each out very thin.
Deep-fry in the hot ghee until golden brown; the dough should puff up a lot, forming a large airy pocket inside.
Remove from the oil and serve hot with chickpea curry.