Place butter in a microwave-safe bowl and microwave for about 30 seconds or until melted.
Remove from microwave and mix with cheese, chili powder and garlic salt.
Preheat grill.
Place corn directly over heat on grilling rack and cook 2-½ minutes on each of 4 sides. It will be slightly charred in some places which makes it that much better.
As soon as it comes off the grill, spread with the utter mixture and serve immediately.
Notes
Make your own garlic salt by adding 1 part garlic powder to 3 parts salt. Store in airtight container.