Base: Place flour, butter, sugar and egg in a bowl and knead to form a dough. Chill for 30 minutes.
Preheat oven to 180 degrees C. Line 2 large baking trays with baking paper.
Roll out dough to a size large enough to be able to cut out 2×26cm rounds of dough. Place on the trays and prick several times with a fork. Bake 15 to 20 minutes. Leave to cool then trim edge neatly. Cover one layer with jelly; place a cake ring around it.
Filling: Beat egg yolks with the sugar, zest and juices in a bowl set over gently simmering water until mixture is the consistency of thick cream. Heat 1/4 cup of the wine and sprinkle on gelatine to dissolve. Stir into cream mixture with remaining wine. Cover and chill.
Cream: Whip the cream until stiff. Remove a quarter and sweeten with the sugar. Place in a piping bag.
Fold the remaining cream into setting wine cream. Pour mixture onto cake base. Chill.
To Assemble: Cut second pastry layer into 16 pieces and place on top of crème. Chill for 6 hours. Sift icing sugar over and decorate with piped cream rosettes and biscuits.