Preheat your oven to 375°F (190°C).

Cut the top off the loaf of bread and scoop out the center, leaving a 1-inch border around the edges to form a bowl. Set aside the bread you remove for dipping.

In a medium bowl, combine the cream cheese, mayonnaise, sour cream, Dijon mustard, lemon juice, garlic powder, onion powder, Old Bay seasoning, and cayenne pepper (if using). Stir until smooth.

Add the cooked shrimp, crab meat, mozzarella cheese, and Parmesan cheese to the mixture. Season with salt and pepper to taste and stir until everything is well combined.

Spoon the seafood mixture into the hollowed-out bread bowl, pressing it down gently to pack it in.

Place the stuffed bread bowl on a baking sheet and bake for 20–25 minutes, or until the filling is hot and bubbly, and the top is golden.

Garnish with fresh parsley and serve with the reserved bread pieces for dipping.