Clean the clams thoroughly. Heat the oil in a saucepan, then add the mirepoix of vegetables and sweat until they are soft. Add the fish stock, white wine and parsley stalks, and bring to the boil. When boiling, add the clams, cover and cook over a high heat until they open, stirring occasionally; this will only take 4 or 5 minutes. When cooked, tip the clams out into a collander, allow to drain until cold, then remove the meat from the shells. Strain the liquor through muslin and reserve.
Cook the carrots in the orange juice, zest and a little water to cover until soft. Drain and place into a food processor or liquidizer until a smooth purée. If the resulting purée is quite wet, dry it out by placing the purée in a heavy-based saucepan over a low heat, stirring occasionally, until some of the moisture has evaporated. Allow to go cold. Beat the eggs, and, when the carrot purée is cold, mix in the eggs together with
While the carrot mousses are cooking, set the clam liquor in a saucepan over a high heat and reduce until it has almost all gone. Then add the remaining cream, return to the boil and reduce until it starts to thicken.