In a bowl, take warm milk and dissolve the sugar. Add the instant yeast to the mixture.
Add the flour and salt and mix to form a soft dough.
Add 1 tbsp butter and knead the dough well for 3-5 minutes.
Apply the other tbsp of butter on the dough, tuck the dough, cover it and let it rest for about 2 hours.
To prepare the filling
Chop the onions, green chilies and coriander leaves finely.
In a pan, add oil and let it heat on a medium flame
Add fennel seeds and let it splutter in the oil.
Add onions, green chilies and ginger-garlic-green chili paste. Saute until onions turn translucent. and the raw smell of the ginger-garlic paste disappears.
Add all the spice powders and the required salt and saute until the masala powders get cooked.
Add a dash of water to the filling and finally add the coriander leaves and mix well.
Switch off the stove and let the filling cool down.
To prepare the khara buns
The dough must have doubled in size. Punch the dough and knead it for a minute and roll it in a flat surface as shown.
Spread the entire filling on the rolled dough.
Roll the dough into a log.
Cut the log into equal sized portions.
Seal the dough edges on one side of the dough ball as shown, leaving the other side to be spiral.
Repeat the same for the rest of the dough balls.
Transfer it to a tray lined with baking paper and cover it with a muslin cloth and let it rest for 20 minutes on the counter-top.
Each bun would have increased in size. Apply some milk on each bun. Bake the buns in a pre-heated oven for 30 minutes at 180°C.
Cool the buns down and serve warm.
Notes
If you are using active dry yeast, then mix it in the warm milk and sugar mixture and let it rest for 15 minutes for it to proof before adding the flour.
Knead until you get a soft and smooth dough.
Let the dough rest for 2 hours. By then, it will be doubled in size.
Use dill leaves instead of coriander leaves, if they are available.
The filling should be moist but not very watery.
The filling prepared should be in a spreadable consistency.
Applying milk on the buns will give the golden-brown color to it.