Shrimp Bisque

1. Heat olive oil and butter in a large saucepan over medium heat. Once butter is melted and oil is hot, add in the shrimp shells, leeks, carrots, garlic, thyme, bay leaf, tomato paste, cayenne and orange zest. Cook for about 10 minutes or until vegetables have softened and shells are red.
2. Add in the sherry and cook for a further 3 minutes. Add in the flour and cook for a couple of minutes longer, stirring with a wooden spoon. Top with the water and orange juice and deglaze the pan, scraping the bits off the bottom of the pan. Add in the single cream and bring just to a boil, reduce heat and simmer for 20 minutes. Add in 1 pound of peeled and deveined shrimp and cook for a few minutes until cooked through.
3. Remove from heat and remove shells. Working in batches, run the soup through a processor then pour through a fine sieve and return to a clean pot.
4. Meanwhile, saute the remaining 8 shrimp for garnish and set aside.
5. Add the pot back over medium-low heat and season. Ladle into four bowls and top with 2 shrimp and a sprig of thyme.