|Mushrooms||5 Ounce (150 Gram)|
|Prawns||4 Ounce (100 Gram)|
|Double cream||60 Milliliter (4 Tablespoon)|
|Flour||1 Ounce (25 Gram)|
|Lemon juice||1 Tablespoon (1 Lemon'S Juice)|
|Butter||2 1⁄4 Ounce (60 Gram)|
|Milk||4 Fluid Ounce (120 Milliliter)|
|White wine||4 Fluid Ounce (120 Milliliter)|
|Onion||1 , peeled|
1. Thaw and bake the vol-au-vent, if frozen. Open the oysters, pour their juices into a saucepan, and bring to the boil. Blanch the oysters for 1 minute. Strain the cooking juices through a fine sieve. Put the oysters aside.
2. Preheat the oven to 230°C (450°F; gas mark 8).
3. Shell the prawns and put aside. Put the shells of the prawns and the juice of the oysters in a saucepan, together with the white wine, bouquet garni and onion. Simmer for 15 minutes. Strain through a fine sieve and put aside.
4. Cut the earthy base from the mushrooms and wash under running water. In a saucepan, over a low heat, melt 30 g (1 1/4 oz) butter, add the mushrooms and lemon juice and cook slowly for 15 minutes.
5. In another saucepan, melt the remaining butter, sprinkle in the flour, and stir over a low heat. Then add the milk, a little at a time, together with the reserved stock. Stir with a wooden spoon until it thickens. Remove from the heat and add 60 ml (4 tbls) cream. Stir well, add the oysters, prawns and mushrooms, and heat.
6. Fill the vol-au-vent cases with the mixture and bake for 2 minutes. Serve at once.