Crack, break or chop the shells into pieces (approximately the size of a thumb nail).

In a large heavy based pot over high heat add a few tbsps of olive oil and sauté the carrot, onion, celery and garlic until soft.

Add the shells and tomato paste and continue to cook a further 5-8 minutes.

Add 2-3 litres of water, enough to cover all the ingredients plus about 5 cm’s, (2-3 inches).

Add the bay leaves, thyme, parsley and a couple pinches of salt and cracked pepper.

Bring the stock to the boil and reduce to a simmer and allow to cook for 2-3 hrs.

Throughout the simmering occasionally skim the impurities and oils off the surface.

Allow stock to cool and strain through a colander, allowing all the solids to drain of all liquids.

Discard the solids and pass the stock through a fine chinois at least twice.

In a medium saucepan over medium heat sauté the eschalots in a little butter and olive oil.

Once they start to go slightly soft add a pinch of cayenne pepper and the orange zest and cook a little further.

Add the Grand Marnier, cook off the alcohol and add the cream and cook on high a further few minutes before adding the strained stock.

Once you’ve added the stock, bring it all to the boil and reduce to medium heat and simmer for a further 30 minutes before passing the bisque through the fine chinois one last time.

Return to stove, taste for seasoning and serve.