Step 1

Whisk one ¼-oz. packet instant yeast (about 2¼ tsp.), ¼ cup plain whole-milk yogurt, 3 Tbsp. sugar, 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, ½ tsp. baking powder, and 1 cup water in a bowl to combine. Using a rubber spatula, mix in 2 cups (250 g) all-purpose flour until a very sticky, almost batter-like dough forms. Cover bowl and let dough sit in a warm, draft-free spot until doubled in size, about 1 hour.

Step 2

While the dough is rising, bring ¾ cup sugar, 1 tsp. ground cardamom, ¼ tsp. kosher salt, and ½ cup water to a boil in small saucepan over medium-high heat, stirring to dissolve sugar. Cook until syrup is slightly thickened, about 3 minutes. Remove from heat and set aside.

Step 3

Pour vegetable oil into a large heavy saucepan to come 3" up sides and fit with thermometer. Heat over medium until thermometer registers 325°.

Step 4

Release dough from sides of bowl with rubber spatula and gently fold to gather. Using a #100 cookie scoop or 2 small spoons and working in batches of 8 or so, carefully drop balls of dough into oil and fry until deep golden brown, about 2 minutes per side. Transfer kalimati to paper towels and let cool slightly.

Step 5

Place kalimati in a medium bowl and pour reserved syrup over; toss to coat. Transfer to a platter and sprinkle with flaky sea salt before serving, if desired.