Melt the butter in a large skillet over high heat until it starts to brown slightly.
Add the corn in a single layer and let it sit untouched for 2 minutes before stirring, repeating until it picks up dark char spots all over, about 6 to 8 minutes total.
Remove from heat and, while still warm, stir in the mayonnaise and cotija cheese.
Add the chili powder, lime juice and cilantro and toss to coat.
Serve warm or at room temperature within 2 hours.
Good to Know
No cotija on hand? Feta is the closest swap in both texture and salt.