Preheat oven to 450 degrees F. Line a baking sheet with parchment paper or a silicone baking mat; set aside.
In a large bowl, combine flour, sugar, baking powder, garlic powder, salt and cayenne pepper, if using.
In a large glass measuring cup or another bowl, whisk together buttermilk and butter. Pour mixture over dry ingredients and stir using a rubber spatula just until moist. Gently fold in cheese.
Using a 1/4-cup measuring cup, scoop the batter evenly onto the prepared baking sheet. Place into oven and bake for 10-12 minutes, or until golden brown.
For the topping, whisk together butter, parsley and garlic powder in a small bowl. Working one at a time, brush the tops of the biscuits with the butter mixture.