Oil + Mustard seeds. Once the mustard seeds splutter, add urad dhal, dry red chilli, turmeric pdr, curryleaves and finely chopped onion. Saute it well and then add tomato(1/2 of a medium) and mango pieces. Saute it well and then add buttermilk as per your required consistency. Add req. amount of salt and a pinch of asafoetida. Garnish with some coriander leaves.