Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a mixing bowl, whisk together the flour, baking powder, garlic powder, onion powder, parsley, salt, and cayenne pepper.
Add the cold, cubed butter to the flour mixture. Use a pastry cutter or your fingers to work the butter into the flour until it resembles coarse crumbs.
Stir in the shredded cheddar cheese until evenly mixed.
Pour in the buttermilk and gently mix until just combined. Be careful not to overmix.
Fold in the lump crab meat, ensuring it's evenly distributed throughout the biscuit dough.
Using a cookie scoop or spoon, drop balls of the dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 10-15 minutes, or until the biscuits are golden brown on top.
While the biscuits are baking, prepare the lemon butter sauce. In a small saucepan over low heat, melt the unsalted butter. Add the lemon juice, zest, and salt. Stir to combine and keep warm.
Once the biscuits are baked, remove them from the oven. Brush with the lemon butter sauce while they're still warm.
Garnish with fresh parsley if desired and serve immediately.