Take a vessel and put chopped mango pieces, Onions, green chillies, salt, chilly powder and salt. To it add 2 cups of water and boil for 5 to 8 mins. until the mango pieces are cooked.
Wash and cook dal separately in a pressure cooker, mash well. Add the cooked dal to the boiled ingredients. Mix well and cook for 5 mins in a low flame and switch off the flame.
Heat 1 table spoon oil in a pan. Add rai and jeera to it. Let rai splutter, add urad dal, red chillies, garlic cloves and curry leaves. Fry for few sec. and add the thadka to the dal. Dal with mango is ready. This is called as mamidikaya pappu in Andhra. Tastes good with Rice. Adding a spoon of ghee to the rice while serving adds a special taste to it.