Soak the tamarind in 1/2 cup of water for 30 minutes and get the juice.
Soak split bengal gram and split pigeon pea for an hour. Drain water.
In a pressure cooker add 1 1/2 cup of water (or as needed) cook the bengal and pigeon pea for 3 - 4 whistle. Once the pressure is gone mash them well. NOTE: you can cook in a pan as well you might need more water.
In a pan heat 2 teaspoon (tsp.) of oil and add the mustard seed. Once the mustard seed stopped splattering.
Add the bitter gourd and cook until its crispy.
Now add the tamarind juice, chili powder, sambar powder, salt to taste and bring to boil.
Now add the coconut paste and bring to boil until the raw smell is gone.
Now add the mashed dal (cooked bengal gram, pigeon pea). Mix well and bring to boil.
Remove from heat then add asafoetida powder and coriander leaf mix well and serve.