Heat butter or olive oil in a large skillet or cast-iron pan over medium-high heat. Add corn kernels and cook for 5-7 minutes, stirring occasionally, until corn is tender and slightly charred. If using frozen corn, cook until heated through and lightly browned.

Remove the skillet from heat and let the corn cool for a few minutes.

In a large bowl, combine mayonnaise, sour cream or crema, ¼ cup cotija cheese, lime juice, chili powder, and smoked paprika (if using). Stir until well combined and smooth.

Add the cooked corn, chopped cilantro, and minced jalapeño (if using) to the dressing mixture. Stir gently to coat all the corn.

Taste and season with salt and freshly ground black pepper as needed. Cotija cheese is salty, so add salt cautiously.

Transfer the Mexican street corn salad to a serving bowl. Garnish with additional crumbled cotija cheese, a sprinkle of chili powder, and extra fresh cilantro before serving.

Serve immediately as a side dish, or chill for at least 30 minutes for flavors to meld.