Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper or grease it lightly.
In a large mixing bowl, combine the flour, baking powder, garlic powder, salt, and cayenne pepper, if using. Whisk to combine.
Fold in the shredded cheddar cheese and chopped parsley until evenly distributed.
In a separate bowl, mix together the melted butter and buttermilk until combined.
Pour the wet ingredients into the dry ingredients and mix gently with a wooden spoon or spatula until just combined. Do not overmix; the dough should be slightly lumpy.
Using a spoon or scoop, drop heaping tablespoons of the dough onto the prepared baking sheet, leaving space between each biscuit.
Bake for 12-15 minutes or until the tops are golden brown.
While the biscuits are baking, prepare the topping by combining melted butter, garlic powder, and salt in a small bowl.
Once the biscuits are done, remove them from the oven and immediately brush the tops with the garlic butter mixture.
Serve warm and enjoy!