Heat 2 tablespoon oil add ½ teaspoon mustard seeds, let it crackle.
Add 2 small red chillies, few curry leaves, let it splutter. Then add 1 tablespoon garlic finely chopped.
Saute until garlic turns golden.
Add 1 medium sized onion finely chopped.
Saute until it turns golden.
Add 3 medium sized tomatoes finely chopped.
Saute until soft and mushy.
Mash it well with a masher.
Give a quick mix. Add salt to taste, ¼ teaspoon turmeric powder and 1 teaspoon red chilli powder.
Mix it well.
Add little water and let it boil well.
Boil well until it becomes thick, switch off.
Onion Tomato Thokku is ready! Enjoy with idli, dosa etc.