Fill a 11.4 L Stockpot with cold water and add the salt. Bring to a boil. Plunge the lobster into the pot, head first. Cover the pot and bring back to a boil. Cook for 9 minutes. Carefully remove the lobster from the pot and set aside until cool enough to handle. Strain the cooking liquid through a fine sieve a few times to remove any residue. Set aside.
Once cooled, shell the lobster. Coarsely chop the meat and refrigerate. Crack the shells into smaller pieces. Thoroughly wash and dry the shells.
In a 4.1 L Chef’s French Oven melt 6 tbsp (90 ml) of the butter over medium-high heat. Add the lobster shells and cook, stirring often, until starting to brown. Add the celery, carrots, leek and garlic. Reduce the heat to medium-low, cover with the lid and cook, stirring occasionally, for 5 minutes.
Add the tomato paste and cook over medium heat, stirring, for 2 minutes. Sprinkle with the flour and cook, stirring, for 1 minute. Deglaze with the wine and cook, stirring, for 2 minutes. Add the chicken stock, herbs, bay leaves, pepper and enough lobster cooking liquid to almost fill the French Oven. Bring to a boil. Reduce the heat and let simmer, partially covered, for 45 minutes, stirring occasionally.
Strain the soup through a fine mesh sieve set over a clean pot or large bowl. Discard the shells and aromatics. (For a thicker soup, blend the softened carrots into a smooth purée and add back into the bisque.) Clean out the Chef’s French Oven.
In the clean Chef’s French Oven, melt the remaining 2 tbsp (30 ml) of the butter. Add the lobster meat and cook for 1 to 2 minutes or until heated through. Drizzle with the lemon juice and set aside. Keep warm.
Strain the soup again directly into the French Oven. Add the cream, cognac and cayenne. Simmer over medium heat until thickened, about 5 to 10 minutes. Adjust the seasoning.
Serve the soup in Classic Coupe Pasta Bowls topped with the lobster meat, chives, celery leaves and a pinch of cayenne.