Before you start cutting the bottle gourd, soak the channa dal in hot water. (This is to speed up cooking of channa dal)
Heat oil in a pressure cooker or in a vessel with a heavy lid.
Once the oil is hot, add the paanch phoron and curry leaves and let it splutter.
Add the onions and green chillies, saute until onion turns translucent.
Add the bottle gourd, channa dal, tomato and the spices (turmeric, coriander, pepper), bay leaf and salt. Stir once.
Add enough water to cover more than half the vegetables (3/4th ).
Close the lid and cook on medium to low flame for 3 whistles. (If you are not using pressure cooker, then after step 4 , fry the bottle gourd till it is almost done, add water, cover and cook on medium heat until the channa dal is fully done. Once the dal is ready it means your curry is ready to serve.)
After the steam settles, open and garnish with coriander and coconut.