Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper.
In a large mixing bowl, combine the flour, baking powder, garlic powder, onion powder, and salt. Whisk to combine.
Add the cold, cubed butter to the dry ingredients. Using a pastry cutter or your fingers, cut the butter into the flour until the mixture resembles coarse crumbs.
Stir in the shredded cheddar cheese.
Pour in the buttermilk and mix until just combined. Do not overmix.
In another bowl, prepare the crab filling by gently folding together the crab meat, mayonnaise, Dijon mustard, Worcestershire sauce, old bay seasoning, parsley, salt, and pepper until well combined.
Using a spoon or cookie scoop, scoop out the biscuit dough and place a portion into the center of each round. Add a spoonful of the crab filling on top, then cover with another small spoonful of dough.
Place the stuffed biscuits on the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 12-15 minutes, or until the biscuits are golden brown.
While the biscuits are baking, prepare the lemon butter by whisking together the melted butter, lemon zest, lemon juice, garlic powder, and salt in a small mixing bowl.
Once the biscuits are done baking, brush them generously with the lemon butter while they are still warm.