A sprinkling of homemade chile-lime salt and grated Parmesan brings the summertime classic of grilled corn with butter to a sublime new level.
Preheat oven to 200 degrees. Finely zest limes onto a parchment-lined baking sheet. Sprinkle 2 teaspoons salt over zest; combine with your hands. Spread mixture into an even layer and bake until dried, about 20 minutes. Let cool completely, then stir in chile powder. Chile-lime salt can be stored in an airtight container at room temperature up to 2 weeks.
Peel back corn husks toward stem ends; remove silks. Rewrap husks and tie with long pieces of husk or twine. Soak corn in a large bowl of water 30 minutes.
Preheat grill to medium-high. Grill corn, turning, until steamed through and charred in places, 12 to 15 minutes. To serve, unwrap husks, brush each ear with butter, sprinkle with chile-lime salt, and sprinkle with cheese. Garnish with chopped jalapenos and cilantro.