In a medium pot over medium heat, melt the ghee and add the finely diced onion, celery, and carrot.
Sauté the vegetables for 5-7 minutes until soft and translucent.
Stir in the minced garlic and tomato paste, cooking for another 2 minutes until the paste darkens slightly.
Pour in the dry sherry to deglaze the pan, scraping up any browned bits from the bottom.
Add the seafood stock and bring the mixture to a gentle simmer for 10 minutes.
For a smooth texture, use an immersion blender to blend the soup base until completely uniform.
In a small bowl, whisk the arrowroot powder into the heavy cream until smooth, then pour it into the soup.
Stir continuously until the bisque thickens slightly, then add the lobster meat to the pot.
Simmer for 3-5 minutes just until the lobster is heated through, being careful not to overcook it.
Season with sea salt and black pepper, then serve hot garnished with fresh minced chives.