Preheat the oven to 400°F. Line a large baking sheet with parchment paper.
In a large bowl, combine flour, baking powder, salt, garlic powder, and mustard powder. Lightly stir together with a fork.
Place the cold butter cubes in the bowl of dry ingredients. Toss to coat them in flour, then use your hands or a pastry cutter to break apart the butter pieces and blend them into the flour. Keep cutting the butter into the flour until the pieces are small and the mixture looks like sand. Work quickly to prevent the butter from melting.
Add the shredded cheddar to the mixture and stir with a fork until evenly incorporated. Add the buttermilk. Mix with a rubber spatula, wooden spoon, or your hands.
Use a large ice cream scoop to scoop the biscuit dough into about 12 biscuits onto the baking sheet. Use your hands to help smooth the sides if necessary. Bake for 14-16 minutes.
While baking, mix the melted butter, parsley, garlic powder, and salt. Once removed from the oven, immediately brush the biscuits with the mixture. Let cool for at least 5 minutes before serving.
Notes
Note: Once cooled, store in a sealed container at room temperature for up to 3 days. Pop in the microwave for 20 seconds for a warm biscuit. Or, let cool and freeze in a sealed container for up to 2 months. To reheat from frozen, microwave for about 1 minute, air fry at 375ºF for 3-5 minutes, or toast in the oven for 5-10 minutes.