2) To make the vichyssoise base, heat the butter and leeks in a small saucepan over low heat and cook until the leeks are softened but not browned. Add the potatoes and water and simmer until the potatoes are tender. Chill and season with salt. Pour into a blender and puree with the cream and blanched spinach to get a light mint green colour. Strain through a fine-mesh sieve.
3) Whisk the creme fraiche to soft peaks in a mixer. Heat 125ml of the vichyssoise base in a medium saucepan. Add the bloomed gelatine to the base. Fold in the whipped creme fraiche and 125ml more of vichyssoise base.
4) For the oyster glaze, bring 3 tbsp of the reserved oyster juices to the boil in a small saucepan. Strain through a coffee filter. Add the bloomed gelatine to the liquid. Allow to cool but not enough to set.
5) Fill the 8 reserved oyster shells about 3/4 full with the vichyssoise mousse and set an oyster on top. Keep cool and brush with the still-liquid oyster glaze. Repeat the brushing until the whole oyster has a shine to it. Garnish with a quenelle of caviar, chive blossom, and dill.
This recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore we cannot make any representation as to the results.