A lobster could hardly hope to meet a more glorious end—a wonderful way to highlight the deliciousness of a single ingredient.
Set aside the best-looking claw piece for the garnish. Chop the rest of the meat and set aside.
In a 4- to 5-quart heavy-bottomed pot over medium heat, melt butter and cook onion, carrots, tomatoes, salt, and pepper until onions are translucent, about 6 minutes. Add the chopped meat, wine, and fish broth or water. Bring to a boil, then cover, reduce heat to low, and simmer 30 minutes. Purée mixture in batches an electric blender until completely smooth (this may take a few minutes). Rinse out saucepan to remove any solids and return to low heat.
Pour purée back into pot. Stir in cream and heat for about 5 minutes. Put the beaten egg yolks in a small bowl. Slowly add about 1⁄4 cup of the hot soup mixture, whisking constantly. Add a bit more soup, whisking again. Pour mixture back into pan, stirring constantly, and gently heat until slightly thickened. Add brandy and more salt to taste. Serve warm, garnished with reserved lobster meat and herbs.