For paprika butter, in a small bowl stir together butter, lime juice, smoked paprika, cumin, and salt. Transfer butter mixture onto a piece of plastic wrap. Shape into a log by rolling the plastic wrap around the butter and rolling the wrapped butter back and forth between your hands. Twist ends of wrap tightly. Chill in the refrigerator at least 1 hour or freeze butter until ready to use. (For longer storage, wrap butter tightly in plastic wrap, then wrap in aluminum foil. Store in the refrigerator for up to 1 week or in the freezer for up to 1 month.)
Remove husks from fresh ears of corn. Scrub with a stiff brush to remove silks; rinse. Cook, covered, in enough boiling lightly salted water to cover for 5 to 7 minutes or until tender.
To serve, unwrap top of paprika butter and, holding on to wrapped sides, run butter over surface of each hot ear of corn.