Take 7-8 pieces of brain and boil them in a water of salt and turmeric (a pinch). Allow them to cook for 5-6 minutes.
For the Melon and Onion Paste:
Fry the melon seeds in oil. Since they are slightly bitter frying them helps takes away the bitterness.
They cook really fast and when you see them browning on the outside, take them out.
Mix them with cold water and blend them in a mixture to make a thick paste.
Cut 4 onions into quarters and boil them. This should take about 3-4 minutes. You can make out by the color and the smell that they are done.
Rinse with some cold water.
Now mix these onion pieces with water and little bit of oil (3-4 Tbsp). Blend them in a mixer to make a thick onion paste. (By adding the oil you can store the paste for a longer time. Also the oil gives it a glaze and a nice whitish colour)
For the Tomato Mixture:
Add a nice dollop of desi ghee in a pan. Once heated add the garlic (half of it) and ginger to it. Let it saute for a minute.
Once it browns add the onions. Mix it well. Once the onions turn nice golden brown add the tomatoes.
Add a pinch of salt at this stage.
Saute this for a couple of minutes. Now add a pinch of red chilli powder and cumin powder.
Mix all well. Once the tomatoes look cooked take the pan off the heat.
For the Gravy:
Heat desi ghee in a pan, add garlic paste, ginger paste and saute.
As the mixture turns brown, add the boiled onion paste and roast it for sometime.
Now add melon seed paste, salt and little bit of white pepper. Roast it.
Once done, set it aside.
Now in another pan heat some butter and saute the garlic.
Add the onion-melon seed base that was made and set aside.
Now add cumin, turmeric, the tomato-onion mixture, salt and red chilli powder into the above mixture.
Break the lamb brains into small pieces with your hands and add them to the mixture.
Coat it well with the masalas.
Add the lime juice and kasoori methi.
Cook for a minute.
Garnish with some coriander leaves and serve hot.