Preheat your oven to 375°F (190°C).

In a large bowl, combine the shrimp, lump crab, cheddar cheese, cream cheese, mayonnaise, mustard, Old Bay seasoning, garlic powder, and black pepper.

Open the biscuit dough and separate the biscuits. Flatten each to about 1/4 inch thick.

Spoon filling onto the center of each flattened biscuit.

Fold each biscuit over the filling and pinch the edges to seal.

Place the filled biscuits on a parchment-lined baking sheet.

Brush the tops with melted butter.

Bake for 15-20 minutes until golden brown.

Cool slightly on the baking sheet for about 5 minutes and garnish with parsley before serving.

Serve warm with a light salad or dipping sauce.