Blend or Whisk Base: In a large mixing bowl, add the chilled curd. Whisk it vigorously until it’s smooth and there are no lumps (you can also use a blender for convenience).
Add Spices ' Herbs: To the smooth yogurt, add the grated ginger, chopped green chili, and the fresh coriander (and mint, if using). Sprinkle in the roasted cumin powder, black salt, and regular salt. Mix everything well so the spices and herbs are evenly distributed. You’ll see the yogurt taking on a speckled green appearance from the herbs – that’s the flavor infusing!
Dilute with Water: Pour in the cold water gradually while continuously whisking (this helps get a smooth, frothy consistency with no curd lumps). Keep whisking until the chaas is well mixed and slightly foamy on top. The traditional method uses a wooden madhani (whisk) to churn the mixture, but a modern whisk or blender works just as well.
Taste and Adjust: Give your chaas a quick taste and adjust salt or spices if needed. Masala chaas should be mildly spicy, tangy, and wonderfully refreshing. If you like more zing, you can add a pinch of regular salt or an extra dash of roasted cumin. For more heat, stir in a bit more green chili (or a pinch of black pepper).
Serve Chilled: Pour the spiced buttermilk into glasses. Garnish each glass with a pinch of extra cumin powder or chaat masala and a few fresh mint/coriander leaves on top for a pop of color. This not only looks inviting but releases a lovely aroma as you sip. Serve the chaas immediately, well-chilled. (If not serving right away, keep it refrigerated – it’s best enjoyed cold.)
Optional – Tempering (Tadka) for Extra Flavor: If you want to channel the Kathiyawadi style or add a special touch, prepare a quick tempering. Heat the teaspoon of ghee in a small pan on medium flame. Once hot, add cumin seeds, curry leaves, and the sliced green chili (if using). Let them sizzle and crackle for a few seconds until the cumin turns aromatic and the curry leaves crisp up. Turn off the heat and carefully pour this fragrant tempering over your prepared chaas. Stir gently. This step is optional but highly recommended if you don’t mind a bit of extra richness – the aromatic ghee and spices floating on top make the chaas irresistible! (Traditionally, masala chaas is usually served without tempering, but this ghee tadka version – often called vagharela chaas in Gujarat – is a delicious regional variation.)