• Preheat oven to 350 degrees F

To prepare filling:

• In a small mixing bowl mix lump crab meat with grated Parmesan, Old Bay, garlic and Ricotta; set aside.
• Cook jumbo shells according to package directions and drain; shake gently to make sure they're dry.
• Heat butter in a small skillet, add dry white wine and marjoram with shrimp and cook until wine dissipates; set aside to cool.
• Once cool, stir shrimp into the crab and Ricotta mixture.

To prepare sauce:

• Heat butter in a large skillet with garlic, add dry white wine and cook a couple of minutes.
• Stir in flour and add the cold milk all at once.
• Stir and as it thickens remove from heat, and stir in the heavy cream, Parmesan and nutmeg.
• Spoon some of the sauce into the bottom of an oblong casserole, just enough to cover. Set the rest of the sauce aside.

Fill the pasta:

• Fill shells with mixture placing filling side up in the baking dish. Continue until filling is used up.
• Add 1/4 cup water to remaining sauce, since it is likely thickened and spoon over the shells in the casserole.
• Cover the sauced shells with shredded cheese.
• Bake uncovered for 25-35 minutes or until lightly browned and bubbly.
• Garnish with crushed seasoned croutons if desired.