cajun shrimp bisque recipe

What it took for 4:
For the Shrimp Stock:
* 1 pound shrimp shells (shrimp to be saved for the bisque)
* 1/2 medium onion, sliced
* 1 tsp whole black peppercorns
* 1 tsp coarse salt
* 2 dried bay leaves
* 1 Tbs. extra-virgin olive oil
* 2 Tbs. fresh parsley
* 6 cups water
For the Bisque:
* 1 pound reserved shrimp
* 4 Tbs. butter
* 1/2 medium onion, finely diced
* 2 celery stalks, finely diced
* 3 cloves garlic, minced
* 2 Tbs. all-purpose flour
* 2 Tbs. tomato paste
* 3 cups milk
* 2 cups shrimp stock
* 1 dried bay leaf
* 4 fresh basil leaves, torn
* 3 Tbs. hot sauce (I used Franks)
* few pinches coarse salt
* 3 scallions, finely sliced