Heat 1 teaspoon of oil in pan on medium heat. Add finely chopped tomatoes.
Cook for 20-25 minutes, stirring in between or until the moisture in tomatoes totally dries out. Set aside.
Pulse ginger-garlic and onion in food processor. You want them really fine for this recipe.
Heat a pan on medium heat and add 2 tablespoons of oil to it.
Once the oil is hot add the chopped ginger and garlic and cook for a minute or two.
Add onion next and cook till the raw smell of the onion goes away completely.
Now add the prepared tomato and mix well. Cook for a minute.
Add garam masala, red chili powder, vinegar and salt. Mix well and cook for another minute.
Now add sugar and mix. The chutney will turn liquidy as the sugar melts.
Keep stirring and cook for another 2-3 minutes till it thickens a bit. Don't cook it for too long because the chutney will thicken as it cools down.
Remove from heat and let it cool down. Once the chutney has cooled down, store it in an airtight container and store in the refrigerator.
Notes
Adjust the garam masala and red chili powder to taste. The chutney gets quite a lot of heat from the garam masala, if you think you can't handle it, reduce the quantity of garam masala to 1 teaspoon.