Wash 1 cup masoor, place it in a pressure cooker with enough water and salt. Pressure cook for 15 to 20 minutes. No need of soaking the grains.
Heat 4 tbsp of oil in a pan and add 1 tsp whole cumin. When it crackles add 1 large chopped onion along with 1 green chili. Fry till onion is soft and pink.
Add 1 tbsp of ginger & garlic paste and fry for some time, till the raw smell disappears.
Add 1 large tomato chopped and fry till it is cooked and oil separates. Then add 1 tbsp red chili powder, 1 tsp coriander powder, 1/2 tsp turmeric powder and 1 tsp cumin powder.
Fry this masala on low flame, add few drops of water if needed. Cook till raw smells turn aromatic. This step is very important so do not hurry. Cook for at least 5 to 7 minutes with the lid on.
Add the boiled masoor along with all the liquid into the masala and stir well. Then add 1/2 tsp of garam masala powder and 1 tbsp of haleem masala powder(optional). Also taste and see if more salt is needed and add accordingly.
Finally, add 1 tbsp lemon juice and chopped coriander leaves. And again cook on low flame for about 10 minutes. Keep stirring while it is cooking.
Cook until you get the desired consistency. Add more water if it is to be served with rice. Or let it be dry if it is to be served with roti.