Step by step
Directions
In a large bowl, combine the lime juice, sour cream, mayonnaise, chiles, and 1/4 tsp. salt. Set aside.
Heat 1 Tbsp. oil in a 12-inch nonstick skillet over high heat until shimmering. Add half the corn, spread it in an even layer, and sprinkle with 1/4 tsp. salt. Cover and cook, without stirring, until the corn touching the pan is charred, about 3 minutes. Take the pan off the heat and leave it covered about 15 seconds, until the popping stops. Transfer the corn to the bowl with the dressing. Repeat with another 1 Tbsp. oil, the remaining corn, and the remaining 1/4 tsp. salt.
Return the empty skillet to medium heat and add the remaining 1 tsp. oil, the garlic, and the chili powder. Cook, stirring constantly, until fragrant, about 30 seconds. Add to the corn, toss to combine, and let cool for at least 15 minutes.
Add the cotija, cilantro, and scallions and toss to combine. Season with salt and up to 1 Tbsp. extra lime juice to taste, and serve.