Chop the onions into thin slices and chop the tomatoes into small cubes.
In a pan add 1 tbsp of cooking oil and add the mustard seeds, urad dal, asafoetida and curry leaves.
Once the dal turns golden brown, add the sliced onions.
Saute for a minute and add the tomatoes.
Add the sambar powder, turmeric powder and salt.
Mix well.
Add 1 cup of water and mix well.
Cover this and cook for 10-12 minutes in medium flame.
Stir in between.
The tomatoes and onions would have cooked well now.
If you want a thick consistency, cook for 2 more minutes.
If you want to serve as a gravy, add little more water and adjust the consistency.
Add the jaggery powder at this stage. This balances the spiciness of the onion tomato thokku.
This is optional, if you don’t want to add, you can skip this. It will no give any sweet taste to the gravy.
Cook for a minute and switch off the flame.
Add 2 tsp sesame oil to this.
Onion tomato gravy is ready to serve.
You can serve this with chapati, poori, idli and dosa too.
This tastes best with curd rice as well.