Preheat the oven to 425°F. Line a 10 x 15-inch jelly roll pan or similar with heavy duty aluminum foil and coat liberally with cooking spray.
Mix together the softened butter, Italian parsley, garlic salt, onion powder and black pepper.
Slather the corn on all sides with ½ of the seasoned butter. Lay side by side on the baking sheet. Cover loosely with foil.
Bake for 25 minutes turning occasionally, or until tender.
Uncover and increase the oven temperature to broil for 3-5 minutes to char slightly.
Brush with the remaining seasoned butter and serve.