Whisk the Yogurt: Take 250 grams of thick yogurt in a bowl. Add 1 tablespoon of gram flour (besan) to it. Whisk it thoroughly until smooth so that no lumps form.
Add Water: Once the besan is mixed perfectly, pour in water to thin out the mixture and whisk again. Keep this mixture aside.
Prepare the Tempering (Tadka): Heat a pan or wok (kadai) on medium flame. Add oil or ghee and let it get hot.
Add Spices: Add mustard seeds, cumin seeds, a pinch of hing, crushed garlic, and curry leaves. Sauté well.
Sauté Chillies & Turmeric: Add the crushed green chillies and turmeric powder. Mix well until the raw smell disappears and the tempering is nicely roasted. Add salt to taste.
Pour the Yogurt Mixture: Lower the heat slightly and carefully pour the whisked yogurt-besan mixture into the pan.
Stir Continuously: Keep the gas flame on medium and stir the Maharashtrian Dahi Kadhi continuously until it comes to a boil. Do not stop stirring, or the yogurt might split.
Garnish and Simmer: Once it boils, add freshly chopped coriander leaves and a little sugar or jaggery to balance the tanginess. Simmer for 2 to 3 minutes.
Serve: Turn off the heat. Your delicious Dahi Kadhi is ready to be served hot!