Soak the dals for atleast 7 - 8 hrs, then cook them separately till done.
Add a few ginger juliannes to it and pressure cook it for 1 whistle combining both of them.
Add the ingredients for makhani gravy in a pressure cooker and cook for 2 whistles.
Cool it, then blend and strain it to get a thick puree.
Heat the butter in a pan.
Add the chopped onions and ginger-garlic paste and fry till the onions are brown and the ginger-garlic paste loses its raw aroma.
Add the garam masala and red chilly powder and fry for 2 - 3 mins.
Add the tomato puree and let it boil for atleast 5 mins, till the oil separates.
Stir in the cream and milk and let it boil for 1 more min.
:- This is called the Makhani gravy.
Add the mashed dal, salt and sugar to it and let it simmer on low heat for 10 - 15 mins.
Check for the seasonings.
Garnish with chopped coriander leaves.
:- Serve hot with Naan/Paratha.