1. Preheat Oven: Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.

2. Mix Dry Ingredients: In a large bowl, whisk together the flour, baking powder, garlic powder, parsley, and salt until well combined.

3. Cut in Butter: Add the cold cubed butter to the mixture. Using a pastry cutter or your fingers, cut the butter into the flour mixture until it resembles coarse crumbs.

4. Add Cheese: Stir in the shredded cheddar cheese until evenly distributed among the mixture.

5. Combine Wet Ingredients: In a separate bowl, whisk together the buttermilk until smooth.

6. Create Dough: Pour the buttermilk into the dry mixture. Stir gently until just combined; do not overmix.

7. Prepare Crab Filling: In another bowl, combine the lump crab meat, mayonnaise, Dijon mustard, and Old Bay seasoning. Stir gently to avoid breaking up the crab lumps.

8. Form Biscuits: Scoop about a tablespoon of biscuit dough, flatten it in your hand, and place a teaspoon of crab mixture in the center. Fold the biscuit dough around it, pinching it closed. Repeat until all crab filling is used.

9. Bake Biscuits: Place the stuffed biscuits on the lined baking sheet about 2 inches apart. Bake in the preheated oven for 15-20 minutes or until they are golden brown.

10. Make Lemon Butter Sauce: While the biscuits bake, melt butter in a saucepan over low heat. Add lemon juice, lemon zest, and salt. Stir until combined and remove from heat.

11. Finishing Touches: Once the biscuits are done, remove them from the oven and brush them with the lemon butter sauce. Garnish with fresh parsley if desired.