In a handi heat mustard oil until it smokes and lower the heat or flame.
Now saute the chopped onions until golden brown, then add the garlic-ginger paste and saute it for a minute.
Rinse the chicken properly and then stir-fry the chicken pieces until its golden brown.
Now mix the spices in it like red chili, turmeric, coriander powder, and salt, and then stir it well.
Then add thinly chopped tomatoes and also add curd, stir it well, cover it with a lid, and let it cook on a slow flame.
Seal the handi with the dough and let it cook on a slow flame for at least 30-40 minutes until the chicken is soft.
Chop the coriander and garnish it on authentic Champaran chicken, serve it hot with rice, chapatti, or litti