Broil the corn on the highest oven rack, rotating every few minutes.
Cut the kernels off the cob and cook in a nonstick skillet with oil over high heat without stirring.
Cook in batches to ensure even cooking.
Cover the skillet to trap steam for better cooking.
Prepare the dressing with mayonnaise, sour cream, and lime juice.
Stir in sliced serrano chile, chili powder, and toasted garlic.
Toss in cilantro, scallions, and crumbled cotija cheese.
