For the grilled corn: Pull the husks of the corn enough to remove the silks, without removing the husks from the stem. Re-wrap the corn in the husks and soak in cold water for 15 minutes.
For the piquillo pepper butter: Blend the butter, piquillo peppers, garlic, thyme, paprika, salt and pepper in a food processor until smooth. Scrape the butter into a bowl, cover and refrigerate for at least 1 hour and up to 24 hours before using. Soften the butter slightly before using.
Heat the grill for direct grilling. Remove the corn from the water, shake and place on the grates of the grill. Cover the grill and cook the corn until tender, about 10 minutes. Remove the corn from the grill, pull the husks back and brush the corn with the piquillo pepper butter. Sprinkle the corn with salt and pepper, Manchego and thyme.