Start by melting butter in a large skillet over medium-high heat. Add the corn (if frozen, rinse and drain first) and cook just until heated through. I like to stir often so each kernel gets coated in butter.
Once the corn is warmed, stir in mayonnaise, sour cream, lime juice, cumin, and chili powder. I find this step gives the dish its signature creamy, tangy flavor that makes it irresistible.
Next, fold in half of the cotija cheese until it melts slightly. Sprinkle the remaining cheese on top, dust with extra chili powder if you like, and garnish with fresh cilantro or green onions. Serve immediately for the best texture.