01 - Preheat oven to 375°F. Line a baking sheet with parchment paper or foil.
02 - Combine cream cheese, mayonnaise, Dijon mustard, lemon juice, Worcestershire sauce, shallot, celery, parsley, Old Bay seasoning, garlic powder, black pepper, and salt in a mixing bowl. Mix until smooth and well incorporated.
03 - Gently fold in the crab meat and chopped shrimp until evenly distributed throughout the mixture. Be careful not to break up the crab lumps too much.
04 - Using a sharp knife, cut a horizontal pocket lengthwise into the side of each salmon fillet, being careful not to cut all the way through to create a deep cavity for stuffing.
05 - Fill each salmon pocket generously with the seafood mixture, pressing lightly to ensure the filling reaches the back of the pocket and mounding slightly on top if needed.
06 - Place the stuffed fillets onto the prepared baking sheet. Brush the tops with melted butter and sprinkle evenly with grated Parmesan cheese.
07 - Bake for 20-25 minutes until the salmon is opaque and flakes easily with a fork, and the filling is hot and lightly golden on top.
08 - Remove from oven and garnish with fresh lemon wedges and additional parsley if desired. Serve immediately while hot.