Preheat the oven to 425°F.
Grate the sharp cheddar cheese until you have 2 cups packed, approximately 8 oz.
Place the grated cheese in the refrigerator to keep it cold while preparing the biscuit dough.
In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, garlic powder, cayenne pepper, and kosher salt.
Add the cold butter chunks to the dry ingredients.
Using a pastry cutter or fork, cut the butter into the flour mixture until the butter is distributed and pea-size pieces remain.
In a glass measuring cup or small bowl, combine the buttermilk and egg.
Whisk until the egg is fully incorporated into the buttermilk.
Pour the buttermilk mixture over the dry ingredients.
Stir gently with a rubber spatula until the dough begins to come together.
Add the chilled shredded cheddar cheese.
Stir until the cheese is evenly distributed throughout the dough.
If the dough becomes difficult to mix with a spatula, lightly flour your hands and gently bring the dough together.
Do not overmix or over-knead the dough.
For drop biscuits, scoop portions of dough directly onto a prepared baking sheet or baking pan and proceed with brushing and baking.
For rolled biscuits, lightly flour a clean work surface.
Transfer the dough to the floured surface.
Gently knead the dough a few times only until it forms a cohesive ball.
Using a rolling pin, roll the dough into a large rectangle, approximately 12 x 16 inches.
Fold the short sides of the dough over the center in thirds, as if folding a business letter.
Turn the dough over so the seam is on the bottom.
Pat or roll the dough again until it is approximately 1 inch thick.
Using a 2 1/2-inch biscuit cutter, cut the dough into biscuits.
Press the cutter straight down without twisting to help the biscuits rise properly.
Gently gather any scraps, pat them together, and cut additional biscuits if needed.
Place the biscuits close together so they are touching in a 9 x 13-inch baking pan or in the center of a baking sheet.
Brush the tops of the biscuits lightly with buttermilk, milk, cream, or half-and-half.
Bake for 15 to 18 minutes, or until the biscuit edges are golden brown and the centers are baked through.
If needed, insert a toothpick into the center of a biscuit to check doneness. It should come out without wet batter.
While the biscuits bake, prepare the garlic butter topping.
In a small bowl, combine the melted butter, minced garlic, and chopped parsley.
Remove the biscuits from the oven.
Immediately brush the hot biscuits generously with the garlic butter topping.
Serve warm.