Step 1: Soak the Horse Gram
Wash the kulth (horse gram) thoroughly under running water. Soak it in enough water overnight or for at least 8 hours. Drain the soaking water and rinse once again before cooking.
Step 2: Cook the Horse Gram
Transfer the soaked horse gram to a pressure cooker with 3 cups of water, turmeric and a little salt. Pressure cook for 4–5 whistles, or until the grains are tender yet hold their shape. Keep the cooked horse gram along with its cooking liquid aside.
Step 3: Prepare the Tempering
Heat mustard oil or desi ghee in a heavy-bottomed kadai until it reaches the smoking point, then allow it to cool slightly. Add the mustard seeds and let them crackle. Stir in the curry leaves, green chillies and grated ginger, and sauté for about 30 seconds until aromatic.
Step 4: Prepare the Masala
If using onion, add it now and sauté until soft and lightly golden. Add the chopped tomatoes and cook over a medium flame until they soften completely and the oil begins to separate.
Sprinkle in the red chilli powder, coriander powder and salt. Mix well and cook for another 2–3 minutes, allowing the spices to blend with the tomato mixture.
Step 5: Prepare the Khatta
Add the cooked horse gram along with its cooking liquid to the kadai. Stir well, then mix in the tamarind pulp (or lemon juice or amchur) and jaggery, if using. Add a little hot water if required to achieve a medium-thick gravy.
Simmer gently over a low flame for 10–12 minutes, stirring occasionally so the flavours come together and the horse gram absorbs the tangy, aromatic gravy.
Step 6: Finish and Serve
Sprinkle the garam masala and mix gently. Garnish with freshly chopped coriander leaves and allow the Kol Ka Khatta to rest for 5 minutes before serving.
Serve hot with steamed rice as part of an authentic Mandyalli Dham, or enjoy it with siddu, chapati or any traditional Himachali meal.