Melt 4 tablespoons butter in a large pot and saute onion, carrots, and celery for 8-10 minutes or until soft.
Remove half of the veggies from the pan and set aside. Add tomato paste to the pot and roast for 1 minute, then add stock, garlic, savory, tarragon, and sherry. Bring to a boil, add pound of Lobster and blend using an immersion blender. Add cream and return to a boil.
In the meantime, make a roux by melting the remaining butter in a nonstick pan and then adding the flour and stirring until mixed and flour begins to brown, about 3 minutes. Stir the roux into the soup.
Once the soup has thickened, add back the reserved veggies and remaining Lobster. Let the lobster warm in the soup for a few minutes, then serve with parmesan.
