Pressure cook the rinsed toor dal for 3 whistles. Turn off the flame and wait until the pressure go off. Mash the cooked dal and keep it aside.
Heat a teaspoon of oil in a pan and add the coriander seeds, chana dal, rice and pepper and fry them on a medium flame till they are golden brown.
Remove from the pan and set aside to cool.
In the same pan, add and fry the red chillies for a minute and set aside.
In a mixie, add the roasted ingredients, roasted chillies and tamarind and grind into a powder. Add coconut and grind it again. Grind everything to a smooth paste using water. Keep it aside.
In a sauce a pan, add the ash gourd pieces and water and cook until they are tender. Drain and set aside.
Combine the cooked ash gourd, ground masala, mashed dal, 1.5 cups of water (adjust to desired consistency), salt and turmeric powder in a vessel.
Let it boil on a medium flame for 10 minutes. Turn off the flame.
Heat 2 tsp of oil in a pan for seasoning. Add the mustard seeds and cumin seeds and let them splutter.
Add the hing, curry leaves and red chilli and stir for a few seconds. Pour this over the stew and combine well.