Preheat Oven: Preheat your oven to 425°F (220°C).

Combine Dry Ingredients: In a large bowl, whisk together the all-purpose flour, granulated sugar, baking powder, garlic powder, cayenne pepper (if using), and kosher salt until well combined.

Cut in Butter: Add the cold, cubed butter to the dry ingredients. Using a pastry blender, two forks, or your fingertips, cut the butter into the flour mixture until it resembles coarse crumbs with some pea-sized pieces of butter remaining. It’s important to keep the butter cold for flaky biscuits.

Combine Buttermilk and Egg: In a liquid measuring cup or small bowl, whisk together the cold buttermilk and the cold egg until well combined.

Combine Wet and Dry Ingredients: Pour the buttermilk mixture over the dry ingredients. Stir gently with a rubber spatula or wooden spoon until just combined. Do not overmix. The dough will be shaggy and slightly sticky.

Add Cheese: Add the cold shredded cheddar cheese to the dough. Stir gently to distribute the cheese evenly.

Prepare Work Surface: Generously flour a clean work surface.

Knead Briefly: Turn the dough out onto the floured surface. Gently knead the dough a couple of times (3-4 times) just to bring it together. Do not overwork the dough.

Roll Out Dough: Using a lightly floured rolling pin, roll the dough out into a large rectangle, about 12×16 inches.

Fold Dough: Fold the short sides of the dough rectangle over the center, like folding a business letter (into thirds).

Turn and Pat/Roll: Turn the dough over so the seam is on the bottom. Gently pat or roll out the dough again until it’s about 1 inch thick. Thick dough makes thick biscuits.

Cut Biscuits: Using a 2 1/2-inch biscuit cutter (or a sharp knife or cookie cutter), cut out biscuits. Press straight down and up with the cutter; do not twist. Twisting can seal the edges and prevent the biscuits from rising properly.

Arrange on Baking Sheet: Place the cut biscuits close together (touching) on an ungreased baking sheet. Touching helps them rise taller. If using a 9×13-inch pan, you may have some leftover dough; shape these into drop biscuits. A 10-inch cast iron skillet can be used, but may not fit all the biscuits (12 is noted)

Brush with Buttermilk: Brush the tops of the biscuits with a little extra buttermilk (or milk, cream, or half-and-half). This helps them brown.

Chill (Optional but Recommended): For extra flaky biscuits, place the baking sheet with the unbaked biscuits in the freezer for 15 minutes before baking.

Bake: Bake in the preheated oven for 15-18 minutes, or until the biscuits are golden brown. If you are unsure if they are done, insert a toothpick into the center; it should come out with no wet batter (moist crumbs are okay).

Make Garlic Butter Topping: While the biscuits are baking, prepare the garlic butter topping. In a small bowl, combine the melted butter, minced garlic, and chopped fresh parsley (or dried parsley). Stir well.

Brush with Topping: As soon as the biscuits come out of the oven, brush the tops generously with the garlic butter mixture.

Cool Slightly and Serve: Let the biscuits cool slightly on the baking sheet before serving.