**Cook the Corn:** Heat a large skillet over medium-high heat. Melt butter (if using), then add the corn. Cook for 5–7 minutes, stirring occasionally, until the corn is lightly charred. Remove from heat and let cool slightly.
**Mix the Dressing:** In a large mixing bowl, whisk together mayonnaise, sour cream, lime juice, chili powder, smoked paprika, salt, and pepper.
**Combine Ingredients:** Add the cooked corn to the dressing, then toss to coat evenly.
**Finish with Toppings:** Fold in chopped cilantro and most of the cotija cheese, reserving a small amount for garnish.
**Serve:** Transfer to a serving dish and sprinkle with the reserved cheese. Serve warm, at room temperature, or chilled.
