Char the corn – Cut kernels off the cob. Heat oil in a large skillet over medium-high, then add corn. Cook 8–10 minutes, stirring occasionally, until slightly charred. (If using frozen corn, make sure it’s dry before cooking.)
Mix dressing – In a large bowl, whisk together mayo, sour cream, garlic, lime juice, chili powder, paprika, salt, and pepper.
Combine – Stir in charred corn, jalapeño, half the cotija, and cilantro. Mix until evenly coated.
Garnish – Top with the remaining cheese, extra cilantro, a sprinkle of chili powder, and lime wedges on the side.
Serve warm, room temp, or chilled — all work well at a BBQ.