Ingredients
1/2 cup plain yogurt (not Greek)
1/2 cup ice-cold water
1/4 teaspoon fine sea salt
1/2 teaspoon cumin seeds
2 teaspoons safflower oil
1 small stem fresh curry leaves (about 10; available at Indian markets, some supermarkets, and kalustyans.com)
1 tablespoon fresh lime juice (from 1/2 lime), plus 1 lime wedge for garnish
1/2 lime, cut into 2 wedges
1 tablespoon sugar
8 fresh mint leaves, plus a mint sprig (preferably flowering) for garnish
Preparation
Drink base: Whisk together yogurt, water, and salt in a bowl until smooth and salt dissolves.
Salty Lime Chaas: Stir lime juice into yogurt base. Pour into a glass, garnish with lime wedge, and serve immediately.
Sweet Lime Chaas: Place lime wedges, sugar, and mint leaves in a glass and smash with a muddling stick or the blunt end of a thick wooden handle until lime juice is extracted, mint leaves are bruised, and mixture is fragrant, about 1 minute. Stir into drink base and garnish with mint sprig; serve immediately.
Curry-Leaf and Cumin Chaas: Toast cumin seeds in a small skillet over medium-high heat, stirring frequently, until fragrant, about 30 seconds. Transfer to a mortar and pestle or spice grinder and coarsely grind. Heat oil in skillet over medium-high heat until shimmering, add curry-leaf stem, and cook, undisturbed, just until leaves darken slightly and curl at edges, about 15 seconds. Stir cooking oil, half of curry leaves, and all but a pinch of cumin into drink base. Pour into a glass, garnish with remaining curry leaves and cumin, and serve immediately.
