Chop the onion, green chillies, tomatoes along with ginger and coriander leaves separately. Now in a bowl, add the curd and whisk it well. chopped tomatoes and make puri.

Next, put a pan on medium flame and heat 3 tsp of butter in it. Add the chopped onions, ginger, green chillies along with green cardamoms for 4 to 5 minutes. Add the chopped tomatoes and cover the pan with a lid. Cook for about 8 to 10 minutes. Then add the curd and cook for another 5 minutes, and pour a cup of water in the pan and cook for a minute. When the gravy is cooked, let it cool at room temperature. When it's cool enough, add it to a mixer jar and blend till smooth and keep.

Now, heat the butter in another pan and add the ground gravy in it along with red chilli powder, garam masala powder, tomato ketchup or sauce and salt.