Bring a large pot of salted water to a boil. Cook the lobsters for about 8-10 minutes until they turn bright red.

Once cooked, remove the lobsters and let them cool. Extract the meat from the claws and tails, and set aside.

In the same pot, melt the butter over medium heat and add the onion, carrot, and celery. Cook for about 5 minutes until softened.

Add the minced garlic and tomato paste to the pot. Stir for a couple of minutes until fragrant.

Pour in the seafood stock and add the thyme. Bring to a simmer, allowing the flavors to meld for about 20 minutes.

Using a blender or immersion blender, puree the soup until smooth.

Return the pureed soup to the pot, then stir in the heavy cream and dry sherry. Heat gently without boiling.

Finally, add the reserved lobster meat to the bisque. Heat through for a few minutes before serving.