Heat 1 tablespoon of oil in a pan and add mustard seeds, urad dal, cumin seeds, and dry red chillies. Saute them for a few seconds.
Add chopped onion and garlic and saute till the onion becomes translucent.
Add chopped tomatoes and salt to the pan and mix well. Cook until the tomatoes are soft and mushy.
Turn off the heat and allow the mixture to cool down.
Transfer the mixture to a blender and blend it into a smooth paste.
In the same pan, add the remaining oil and asafoetida. Add the tomato mixture to the pan and cook for 1-2 minutes.
Adjust salt and spice according to taste.
Transfer the chutney to a serving bowl.