Stir ¾ cup grated Cotija cheese, ½ cup mayonnaise, 2 tablespoons to ¼ cup Mexican crema (use 2 tablespoons if the crema is thin like heavy cream), ¼ cup lime juice, ½ teaspoon cayenne pepper if using, and ¼ teaspoon smoked paprika together in a medium bowl.

Place 6 husked ears of corn on a rimmed baking sheet. Drizzle with 1 tablespoon vegetable oil and use your hands to coat and flip the corn until evenly coated. Season all over with ½ teaspoon kosher salt.

Arrange a rack in the upper third of the oven and heat the oven to 425ºF. Place the baking sheet in the oven and roast, flipping the corn halfway through, until starting to brown, about 15 minutes total. Turn the broiler to high. Broil, flipping the corn halfway through, until the corn is charred and browned in spots all over, 7 to 9 minutes total.

Heat an outdoor grill for direct, medium-high heat (450ºF to 475ºF). Place the corn on the grill (reserve the baking sheet). Cover and grill, turning the ears every 3 to 4 minutes, until the corn is tender and slightly charred in spots on all sides, 15 to 20 minutes total. Return the corn to the baking sheet.

Let the corn sit until cool enough to handle, about 5 minutes.

Generously spread the Cotija mixture over all sides of the corn. Sprinkle with Tajín seasoning and garnish with chopped fresh cilantro leaves if desired. Serve with any remaining Cotija mixture.