4 tablespoons unsalted butter, divided
2 bay leaves, divided
2 carrots, peeled, chopped
2 celery stalks, chopped
1 cup chopped onions
½ cup brandy
¼ cup long-grain white rice
2 tablespoons tomato paste
3 springs fresh flat-leaf parsley
3 springs fresh thyme
Pinch to ¼ teaspoon cayenne pepper
Salt and freshly ground pepper
½ cup heavy cream
3 tablespoons fresh lemon juice
¼ cup finely chopped fresh chives
1. Melt 1 tablespoon butter of the butter in a large (6 to 8 quart) heavy pot over medium-high heat. Add the prawns shells and cook, stirring frequently, until they begin to brown, about 5 minutes. Add 1 bay leaf and 8 cups water. Simmer uncovered for 25 minutes.
2. Set a fine-mesh strainer over a large bowl. Strain, discarding the solids. The prawn stock can be made 3 days ahead. Let cool slightly; chill uncovered until cold, then cover and keep chilled.
3. Melt 1 tablespoon of the butter in a large heavy pot over medium heat. Add the prawns and cook, stirring occasionally, until just opaque in the center, about 3-4 minutes. Transfer the prawns to a plate.
4. Add the remaining 2 tablespoons butter to same pot. Add the carrots, celery, and onions and cook over medium heat, stirring frequently, until very soft, about 20 minutes.
5. Remove the pot from the heat and add the brandy. Return the pot to heat and stir until the brandy is almost evaporated, about 2-3 minutes. Add the rice and tomato paste; stir for 1 minute.
6. Add the prawns stock, remaining bay leaf, parsley, thyme, and pinch cayenne. Simmer uncovered until the flavors meld and the rice is soft, about 20 minutes. Season with ½ teaspoon salt and a sprinkling black pepper. Reserve 3 to 4 prawns (depending on size) for garnish and stir the remaining prawns into the bisque. Remove the parsley, thyme, and bay leaf.
7. Working in batches, purée the bisque in a blender until smooth. Pour through a fine-mesh strainer set over a clean pot. Discard solids in strainer.
8. Stir in the cream and reheat the bisque over medium heat. Stir in the lemon juice. Season to taste with salt, pepper, and more cayenne, if desired.
9. Mince the reserved prawns and mix with chives in a small bowl. Place 1 heaping tablespoon prawns mixture in the center of large, shallow soup bowls. Ladle the bisque around the garnish and serve hot.