Heat the olive oil in a pan over medium heat.
Sauté the cumin and mustard seeds for a minute or until they become fragrant.
Add the chopped onions, chopped tomatoes, red chilli, minced garlic, and salt to the pan.
Cook on medium heat for about 15-20 minutes until the tomatoes become soft and pulpy.
Stir in the red wine vinegar and brown sugar, and cook for another 5-10 minutes until the chutney thickens.
Remove the pan from heat and let the chutney cool.
Blend the chutney to your desired consistency, if preferred.
Serve with your favourite dish or store in an airtight container in the refrigerator for up to 4-6 weeks.