Prepare your grill to medium-high heat.
Pull the husks back from each ear of corn. Use your fingers to remove as much of the silk for each ear of corn. Bring the husks back around the ear of corn, and use string, or a strand of the husk to tie the tops of the husks so they stay on the corn. (It's okay if some of the corn is visible through the husks).
8 ears fresh corn
In a medium bowl, mix together the Mexican crema (or creme friache or sour cream), mayonnaise, ½ cup crumbled Cotija, cayenne, lime juice, and salt.
½ cup Mexican crema, ¼ cup mayonnaise, ¾ cup Cotija cheese, ¼ tsp cayenne pepper, 1 lime, 1 tsp salt
Cook corn in husks on the grill for about 8 to 10 minutes, until the husks have begun to char. Watch them closely, and move them around the grill often with metal tongs. The husks will burn easily, so, stay with them!
Remove the corn from the grill, and when cool enough to handle, remove the husks from each ear of corn, leaving a portion of the stalk in place. Place the corn back on the grill for about 12 to 15 minutes, until kernels are browned in spots, turning occasionally.
Remove corn from the grill and place on a large cutting board.
Brush with the cream mixture all over the corn while still hot.
Place on a platter and sprinkle on the remaining Cotija cheese, the cilantro, freshly squeezed lime, and extra cayenne, if desired. Serve at once.
½ cup cilantro, Lime wedges