Stir the warm milk, sugar and yeast together in a jug. Leave for 5 to 10 minutes, until a light foam appears.
Whisk the yoghurt, egg and vegetable oil in a large bowl. Pour in the yeast mixture and stir until evenly combined.
Mix 450g flour, the baking powder and salt in a separate bowl. Add to the wet ingredients and stir until a soft, rough dough forms.
Knead by hand for 8 to 10 minutes, or with a dough hook for 6 minutes. The dough should become smoother while remaining lightly tacky. Add the reserved flour a tablespoon at a time only if it remains unmanageably wet.
Place in a lightly oiled bowl, cover and prove in a warm place for 60 to 90 minutes, until nearly doubled.
Turn the dough onto a lightly floured surface and divide it into 6 equal pieces. Shape them into balls, cover and rest for 20 minutes.
Heat a heavy frying pan, cast iron skillet or tawa over medium high heat for 5 minutes. Roll one dough ball into a thin oval approximately 3mm thick. Press in optional coriander or nigella seeds, then 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, brush with melted ghee and cover loosely with a clean tea towel. Repeat with the remaining dough, adjusting the heat if the pan begins smoking heavily.