Heat oil, splutter mustard seeds and pop in cumin seeds. Saute finely chopped garlic and a spring of curry leaves.
Add chopped onion and tomato into it and saute for a minute.
Throw in chopped vegetables (bottle gourd), turmeric powder, chilli powder, sambar powder and salt. mix well and add water. Pressure cook for 3-4 whistles. Open and mash slightly.
meanwhile pressure cook dal separately and mash it well.
add cooked dal, coconut paste to the kootu and mix well. give it a boil.