1. Sauté the Vegetables:
   • In a large pot, melt the butter over medium heat. Add the chopped onion, celery, and carrot. Cook for about 5 minutes, until the vegetables are softened.
   • Add the minced garlic and cook for another minute until fragrant.
2. Make the Roux:
   • Sprinkle the flour over the sautéed vegetables and stir to coat. Cook the flour for 2-3 minutes, stirring constantly, until it’s lightly browned.
3. Add the Liquids:
   • Gradually whisk in the seafood stock, ensuring no lumps form. Add the tomato paste, Old Bay seasoning, and cayenne pepper if using.
   • Bring the mixture to a simmer and cook for 10 minutes to allow the flavors to develop.
4. Blend the Bisque:
   • If you prefer a smoother bisque, use an immersion blender to blend the soup until smooth. Alternatively, you can transfer the soup to a blender in batches, then return it to the pot.
5. Add the Cream, Milk, and Sherry:
   • Stir in the heavy cream, milk, and dry sherry (if using). Reduce the heat to low and simmer the bisque for another 5 minutes.
6. Add the Seafood:
   • Stir in the shrimp and crab meat. Cook for 5-7 minutes, or until the shrimp are pink and cooked through.
7. Season and Serve:
   • Taste the bisque and adjust the seasoning with salt and pepper as needed.
   • Ladle the bisque into bowls and garnish with chopped chives or parsley.

Enjoy your Creamy Crab and Shrimp Seafood Bisque as a decadent and comforting seafood soup!