In medium saucepan, bring chicken stock to a boil. Cut through shell of lobster tails. Place in boiling stock. Cover pan; reduce heat to simmer. Simmer 4 to 5 minutes or until flesh is opaque. Remove lobster tails and chill in cold water to stop cooking. Reserve broth. When cool enough to handle, remove lobster meat from shells and chop coarsely.

In large saucepan, melt butter over medium heat. Add onion, celery and carrots. Cook 6 to 7 minutes or until tender but not browned, stirring occasionally. Stir in tarragon and thyme. Stir in flour until blended. Stir in 1 & 1/2 cups of the broth; bring to a boil. Boil 1 minute or until thick. Stir in lobster, half-and-half and beans. Cook until thoroughly heated. Add small amounts of remaining stock for desired consistency.

Tip: You can substitute 1 cup of any kind of lobster meat. If the lobster is already cooked, just stir in at the end.