Stir the warm water, sugar and yeast together in a jug. Leave for 5 to 10 minutes, until a light foam appears.
Mix 450g flour, the baking powder and salt in a large bowl. Pour in the yeast mixture and vegetable oil, then stir until a soft dough forms.
Knead by hand for 8 to 10 minutes, or with a dough hook for 6 minutes. The dough should become smoother and elastic while remaining tacky. Add the reserved flour a tablespoon at a time only if it is unmanageably wet.
Place the dough in a lightly oiled bowl, cover and prove in a warm place for 60 to 90 minutes, until almost doubled.
Divide into 6 equal pieces, shape into balls and place them on a lightly floured tray. Cover and rest for 30 minutes.
Melt the ghee in a small frying pan over medium low heat. Add the garlic and cook for 1 to 2 minutes, stirring, until fragrant and very lightly golden. Remove from the heat and stir in the coriander.
Preheat a heavy frying pan, cast iron skillet or tawa over medium high heat for 5 minutes. Roll one dough ball into an oval approximately 3mm thick and brush the underside lightly with water.
Place the wet side against the dry pan. Cook for 60 to 90 seconds, until bubbles rise and the base develops dark golden patches. Turn and cook for another 45 to 60 seconds, until coloured and cooked through.
Transfer to a plate and brush generously with the garlic ghee. Cover loosely with a clean tea towel and repeat with the remaining dough.