Prepare the Lobster Tails

1. Bring a pot of salted water to a boil. Add the lobster tails and cook for 4-5 minutes, or until the shells turn bright red.
2. Remove the lobster tails, cool slightly, then remove the meat from the shells. Chop into bite-sized pieces and set aside. Save the shells for added flavor if desired.

2. Sauté the Vegetables

1. In a large pot, melt butter over medium heat.
2. Add the finely chopped onion, celery, and carrots. Sauté for 6-7 minutes until softened.
3. Stir in garlic and tomato paste, cooking for an additional 2 minutes until fragrant.

3. Build the Base

1. Sprinkle flour over the vegetable mixture, stirring to coat. Cook for 1 minute.
2. Slowly pour in the seafood stock and white wine, stirring constantly to avoid lumps.
3. Add the bay leaf, thyme sprigs, salt, and pepper. Bring the mixture to a gentle simmer.

4. Simmer and Blend

1. Simmer uncovered for 30 minutes, stirring occasionally to develop the flavors.
2. Remove the bay leaf and thyme sprigs. Blend the soup in batches using a blender, or use an immersion blender to puree the mixture until smooth. Return the bisque to the pot.

5. Add Cream and Sherry

1. Stir in the heavy cream and optional sherry for added richness and depth of flavor.
2. Add the cooked lobster meat and gently heat through for 2-3 minutes. Avoid boiling to prevent overcooking the lobster.

6. Serve and Garnish

1. Ladle the bisque into bowls.
2. Garnish with freshly chopped chives and a drizzle of sherry if desired. Serve immediately with crusty bread or crackers.