Boil chaap in hot water and remove the sticks out of it and cut each chaap into 4-5 pieces,add bit of salt and kitchen King masala and keep it aside for 10 minutes.
Take oil in a wok, add gingergarlic paste,saute them and then add sliced onions,saute them till brown
Now add tomatoes paste and add salt,red chilly,turmeric and let it simmer for 10 minutes till oil seperates out.
Now add chaap to it and add water and keep it on sim so that chaap absorbs masala.
Now add vinegar and tomato sauce and butter and cook till gravy thickens