Rinse and chop tomatoes and keep aside.
Heat a pan, add coconut oil and mustard seeds. Once mustard crackles, add chana dal and dry red chilies.
Once dal is roasted brown, add hing or asafoetida and the finely chopped tomatoes.
Reduce the flame and allow the tomatoes to cook, until mushy.
In the meanwhile, whisk 1 cup of yogurt until smooth. Mince coconut, cumin seeds and green chilies in a mixer grinder jar until coarse. Keep this aside.
Switch off the flame, remove the tomatoes from the pan onto a serving bowl and allow it to cool. Note - Chuck the bowl in the refrigerator to speed up the process.
To the cooled tomatoes, add the coconut mixture and whisked yogurt. Season with salt and mix well.
Garnish tomato raita with finely chopped coriander. Serve immediately or store in refrigerator until ready to serve.