Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a mixing bowl, combine the flour, baking powder, garlic powder, onion powder, salt, and black pepper. Mix well.
Add the shredded cheddar cheese to the dry ingredients, mixing until well combined.
Cut the cold diced butter into the flour mixture using a pastry cutter or your fingers until the mixture resembles coarse crumbs.
Stir in the buttermilk and fresh parsley until just combined. Do not overmix.
In a separate bowl, prepare the crab filling by mixing together the crab meat, cream cheese, mayonnaise, lemon juice, Dijon mustard, Old Bay seasoning, parsley, salt, and pepper until smooth.
Using a spoon, scoop out a portion of the biscuit dough and flatten it in your hand. Place a teaspoon of the crab filling in the center and fold the dough over to cover the filling. Shape it back into a ball and place it on the baking sheet. Repeat with the remaining dough and filling.
In a small bowl, mix together the melted butter and garlic powder. Brush this mixture over the tops of the stuffed biscuits.
Bake the biscuits in the preheated oven for about 20 minutes, or until they are golden brown.
Remove the biscuits from the oven and brush with any remaining garlic butter topping. Sprinkle with additional fresh parsley, if desired.
Serve warm and enjoy!