Whisk the sour yoghurt in a bowl. Add the chopped onion, ginger and green chilly, salt and cumin powder. Mix well.
Open the boondi pack, measure half a cup, put it on a cookie sheet and roast in the oven at 350 degrees Fahrenheit for 5 minutes just to make it a little extra crisp.
Deep fry the curry leaves (wash and dry them between paper towels before frying) in oil. Remove when they turn crisp and drain on paper towels.
Crush the crisp curry leaves on the spiced yoghurt and top it with the crispy boondi just before serving.
Serve with rice, naan, lentil or meat dishes. Mix the boondi in the raita and enjoy.