Step 1: Preheat your oven to 375°F (190°C). Carefully slice off the top of each bread bowl and hollow out the inside, leaving a 1-inch thick shell. Reserve the scooped-out bread for dipping if desired.
Step 2: In a large skillet, heat the olive oil over medium heat. Add the chopped shrimp and cook for 2-3 minutes until they turn pink and opaque. Remove the shrimp from the skillet and set aside.
Step 3: In the same skillet, melt the butter over medium heat. Whisk in the all-purpose flour and cook for 1 minute, stirring constantly, to create a roux.
Step 4: Gradually whisk in the whole milk and heavy cream until the mixture is smooth. Bring to a simmer, stirring constantly, until the sauce thickens.
Step 5: Remove the skillet from the heat. Stir in the Parmesan cheese, half (1/2 cup) of the shredded Gruyere, Old Bay seasoning, garlic powder, salt, and black pepper until the cheeses are melted and the sauce is smooth.
Step 6: Gently fold in the cooked shrimp, lump crab meat, chopped fresh parsley, fresh dill, and fresh lemon juice into the cheese sauce.
Step 7: Spoon the seafood mixture evenly into the hollowed bread bowls. Top each with the remaining 1/2 cup of shredded Gruyere cheese.
Step 8: Place the filled bread bowls on a baking sheet. Bake for 20-25 minutes, or until the filling is hot and bubbly and the cheese topping is melted and golden brown.
Step 9: Serve immediately, perhaps with the reserved toasted bread cubes for dipping.