Wash the beans and soak it overnight or atleast for 6 to 8 hours and pressure cook by adding 2/3 to 3/4 cup of water for three whistles.
Do not drain the water. Set it aside.
Prepare the Thengai Paal Kuzhambu-
Heat a pan or kadai and add oil.
When the oil is hot, add the mustard seeds. As they start to splutter, add the fenugreek powder, half of the curry leaves, and asafoetida.
Let it cook for 30 seconds and add the chopped onions.
Cook until the onions turn soft. Then add the tomatoes, salt, and turmeric powder. Cook until the tomato becomes soft and mushy.
Now mix 1.5 tsp of tamarind paste in 1 cup of water and add it to the tomato-base. Add the jaggery as well.
After about 3 minutes, add the sambar powder and mix it well. You can even mix it with 1/4 cup of water and add it to the kuzhambu. Bring it to a boil.
Now add the cooked beans with the water and mix thoroughly. Simmer it for two to three minutes.
Finally, add the coconut milk and mix it all. Reduce the heat to medium-low and simmer it. As it becomes frothy on top, add the remaining curry leaves and turn off the heat.
Serve hot with rice.
Prepare Fenugreek powder (Skip if you are using store-bought)
Roast about a tbsp of fenugreek seeds without adding any oil until it turns light brown. Let it cool and grind it coarsely. We need 1 tsp of this powder for this recipe. You can use the rest for tamarind rice or pickle or for other kuzhambu recipes.
Homemade Coconut Milk- (Skip if you are using store-bought)
For this recipe, I went with store-bought coconut milk (chaokoh brand). You can prepare the same at home too. For one-half of freshly grated coconut (break the coconut into two halves and grate the one-half), add 1 cup of lukewarm water and grind it. Squeeze out the milk, and this is the first and thick coconut milk. Grind again by adding 1 cup of water and extracting the liquid, which is the second and thin coconut milk. Use the first milk for this recipe.
As I mentioned before, you can use any dried beans of your choice.
Adjust the sambar powder, salt according to your preference.
The coconut milk balances the spiciness and tanginess. So add the tamarind and sambar powder accordingly.
Jaggery is optional.
I did not include garlic. Five to ten garlic cloves can be added for this recipe.