Cream butter in a medium bowl until smooth. Mix in cilantro, lime juice, and cayenne pepper until thoroughly combined. Cover and refrigerate until flavors blend, about 1 hour.

Meanwhile, peel husks back from ears of corn starting at the top, leaving husks attached at the bottom of the ears. Remove all of the corn silk and close husks over ears again. Cover corn ears with cold water in a large bowl until husks are thoroughly soaked, about 20 minutes.

Preheat the grill for medium heat and lightly oil the grate.

Place corn in husks onto the hot grate and cook in the preheated grill with the lid closed until husks are charred and corn kernels are tender, 20 to 25 minutes, turning often. Remove husks and serve immediately with cilantro lime butter.