Mix all the ingredients except the cornstarch in a thick-bottomed pan. Turn the heat on to medium.
Meanwhile, in a separate small bowl, mix the cornstarch with 1 teaspoon water. Add this mixture to the chutney.
Let the chutney come to a rolling boil. Turn the heat off after it keeps boiling for 2-3 minutes. If the chutney is not yet thick to your liking, add 1/4 tsp more cornstarch (mixed with 1/2 tsp water) and boil again for 2-3 minutes.
Once the chutney cools down, store in the refrigerator in a clean glass bottle.
Serving Suggestion: Add 2 teaspoons chutney to a cup of crispy rice cereal. Mix a pinch of salt and red chile powder, a spoonful of diced red onions, and chopped cilantro for a quick snack. Or enjoy with aloo chaat.