Sauté chopped onions, celery, and carrots in 1/2 cup of butter until softened.

Add lobster shells and white wine to the vegetables.

Cook until the lobster shells turn red.

Pour in the fumet, clam juice, and chicken stock.

Simmer the mixture for one hour.

Add Arborio rice and continue to simmer for another thirty minutes.

Process the rice mixture using a food mill.

Pass the mixture through a small tamis for a smooth texture.

Bring the bisque to a boil.

Stir in heavy cream and cognac.

Add saffron and season with salt and pepper to your taste preference.