Once the oil is hot, add mustard seeds, cumin seeds, fenugreek seeds, hing and curry leaves and let them crackle for a few seconds.
Add onion and green chilli and fry for 2-3 minutes until onion turns translucent.
Add ginger and garlic and fry for another 2 minutes.
Now add tomato, red chilli powder, tamarind and salt to taste and mix well.
Cover the pan and cook on low heat for 30-35 minutes.
Stir a few times in between.
Remove the pan from heat and let the chutney cool for a bit.
Transfer the chutney in a blender and blend to make a coarse chutney.
Serve hot with rice, idli or dosa.
Andhra style tomato chutney is spicier and uses red chillies instead of green chillies. You will also need some urad and chana dal to make it. Add the dal in the oil and let them turn golden brown before adding other ingredients.You can also use Dry Red Chilli paste instead of red chili powder to enhance the color of this chutney even more.Onions are an important ingredient in this chutney, it adds a mild sweet taste and also compensates the tang from tomatoes. But you can always avoid adding onion and garlic if you are planning to make a No Onion No Garlic Chutney.If you do not like it to be very spicy, you can reduce the number of green chilies or even skip adding it.Tempering this Chutney is optional, but you can add in for extra flavor.