Instructions

Line rimmed baking sheet with double layer of paper towels. Spread 1 pound squid, bodies sliced crosswise ¾ inch thick, extra-long tentacles trimmed to match length of shorter ones, in even layer; top with another double layer of paper towels; and press well while rubbing lightly to dry. Transfer squid to bowl, add ½ teaspoon table salt and ⅛ teaspoon sugar, and toss to coat evenly.
Heat 1 tablespoon vegetable oil in 12-inch nonstick skillet over high heat until just smoking. Add half of squid and, working quickly, use spatula to spread into even layer. Cook, without stirring, for 90 seconds. Shake pan and stir quickly to redistribute squid, then continue to cook, without stirring, for 1 minute. Transfer squid to clean medium bowl. Repeat with remaining 1 tablespoon oil and squid.
Place now-empty skillet over medium-low heat and add 2 tablespoons ghee. When ghee is melted, add ½ serrano chile, halved lengthwise, and cook, stirring frequently, until fragrant, about 30 seconds. Add 1 teaspoon brown mustard seeds, 1 teaspoon cumin seeds, 1 teaspoon coriander seeds, lightly crushed, and remaining ¼ teaspoon salt, and continue to cook, stirring frequently, until seeds begin to sizzle and crackle, about 1 minute. Stir in 2 tablespoons lime juice and remove skillet from heat. 
4. Return squid to pan and toss until evenly coated. Transfer to serving bowl and sprinkle with ¼ cup chopped cilantro. Serve immediately, passing lime wedges separately.