Wash and soak the black lentils and kidney beans overnight in plenty of water.

Drain the soaking water and transfer to a pressure cooker with salt and 3 1/2 cups fresh water. Pressure cook on high-medium heat for 10 whistles, then lower heat for 10 additional minutes. Release pressure naturally.

Mash some of the lentils with a potato masher for creaminess. Keep simmering on the lowest heat.

In a separate pan, heat butter and ghee. Add grated onion and cook 6-7 minutes until light golden. Add ginger garlic paste and cook 1-2 minutes.

Stir in tomato puree and cook 2 minutes until oil separates. Add the cooked lentils and mix thoroughly.

Add garam masala, Kashmiri chili powder, and salt. Mix well. Add water and simmer uncovered on low heat for 45 minutes, stirring every 10 minutes.

Add sugar, then stir in remaining butter and cream. Simmer 10 more minutes.

Garnish with a swirl of cream and a pat of butter. Serve hot with naan, roti, or jeera rice.