Pulse through the coriander leaves and green chilli to grind coarsely.
Add it to the rest of the ingredients for aloo stuffing, mix well and set aside.
To prepare the Kulcha dough - In a mixing bowl, add flour along with salt, sugar, cooking soda and baking powder. Mix well.
Make a well in the center and add the curd and milk. Mix well. The flour would be crumbly. Add few tablespoon of milk if required and knead it into a soft pliable dough.
Add a teaspoon of oil on top and let it rest for at least an hour.
Divide the dough into six equal portions. Similarly divide the potato stuffing into six equal portions.
Take a ball of dough and roll it into a medium sized thick circle. Add one portion of the potato stuffing at the center and close it by bringing all edges together.
Sprinkle some sesame/onion seeds (if adding) and slightly press them. Add few drops of oil on top and gently roll the dough into a circle.
Meanwhile heat a heavy tawa (like cast iron) and once is it hot enough, place the prepared Aloo Kulcha with plain side facing down. Cook it on medium heat. In few seconds, there would be bubbles coming up.
Gently flip it to cook on the other side on medium flame. Apply oil/butter.
Flip again and apply oil/butter on the other side. As the kulcha gains a lot of golden brown spots, remove it onto a plate. Repeat the same with rest of the dough.