Before you start making the soup, make sure to soak the Black chickpeas (kala chana) overnight. If you want, you can also soak chana dal for 2 to 3 hours (I did not soak it).
To a pan on medium-low heat, add besan. Dry roast the besan, stirring continuously for 3 to 4 minutes until it has a nice roasted aroma. Remove pan from heat.Transfer the roasted besan to a glass jar or bowl and add 1/2 cup water to it. Using a wire whisk, mix it all together until the besan and water are well combined. Set this aside.
Press the saute button on the Instant Pot. Once it displays hot, add the oil and then add the bay leaf, dried red chili, cumin seeds and mustard seeds. Let the cumin seeds crackle and mustard seeds pop.
Then add the chopped onion and minced garlic. Add 1/4 teaspoon salt along with the onions (this helps them in cooking faster).Cook for 2 to 3 minutes until the onions soften.
Then add the spices- turmeric, coriander powder, paprika. Cook for around 45 seconds.
Then add the besan-water mixture that we had prepared earlier and stir. Drain the soaked kala chana and add it to the pot along with chana dal. Give it a stir.
Add 4 cups water and stir everything. Add remaining 3/4 teaspoon of salt. You can adjust the amount of salt to taste.Also, add tamarind concentrate and stir.
Close the pot with the lid and press the manual or pressure cook button. Cook on high pressure for 20 minutes with the pressure valve in sealing position. Quick release the pressure.
Open the lid, add soup to serving bowls. Break samosa into 3-4 parts and add to soup bowl. Depending on the size of the soup bowl, you can add 1 or 2 samosa per soup bowl. Top with shredded green & purple cabbage, sliced carrots, cilantro!
Stove-top Instructions
If you don't have a Instant Pot, cook the chana dal and kala chana first using a stove-top pressure cooker. Then in a pan, add oil and then follow all the steps as it is until adding water. Once you have added the water, let the soup simmer for 15 to 20 minutes on medium heat. You may need to add more water as water evaporates on stove-top. Add samosa and serve with toppings.
Notes
Nutritional info does not include the calories for samosa and other toppings. Please see the samosa recipe for samosa calories.
You can use toor dal in place of chana dal. You can also skip the kala chana. If you skip the kala chana and use toor dal, then you would need to pressure cook the soup for 8 minutes only.
This soup has a thin consistency. If you prefer a thick soup, you can add some cornstarch slurry to the soup once it's cooked. Some people also add potatoes to the soup to make it thick but I like this soup without the potato.
The tamarind concentrate can be easily found at Indian grocery stores. I have used only 1 teaspoon of it here since it's super strong in flavor. While testing this recipe, I did use 3 teaspoons of tamarind concentrate once and it made the soup very tangy. But every brand can be different so you can adjust the amount accordingly.
If you want to chana dal to be super soft in the soup, you can soak it for 3 to 4 hours before using in the recipe.
The soup base isn't spicy at all. Since the samosa has so much flavor, and you eat this soup along with samosa I like to keep the base simple. But if you want, you can add chili powder or green chilies to the soup base.
The main flavor of this soup comes from having the soup with samosa - that's the uniqueness of this soup so please don't have this soup without it!