Place egg yolks in a large mixing bowl; beat 6 minutes at high speed of electric mixer or until thick and lemon colored. Combine water, lemon rind, and juice; add to egg yolks. Beat on low speed of electric mixer until thoroughly blended. Beat at medium speed an additional 4 minutes or until thick.
Gradually beat in sugar and salt; continue beating about 5 to 6 minutes until smooth.
Combine flour and baking powder. Sprinkle flour mixture over yolk mixture 1/2 cup at a time; carefully fold in. Gently fold melted butter into batter.
Beat egg whites (at room temperature) until soft peaks form. Gently fold about 1 cup of egg whites into yolk mixture. Gently fold yolk mixture into remaining egg whites.
Pour batter into an ungreased 10-inch tube pan, spreading evenly with a spatula. Bake at 350° for 35 minutes or until cake springs back when lightly touched. Remove cake from oven, and invert pan. Cool cake 40 minutes, and remove cake from pan.
Slice cake horizontally, making 2 separate layers. Pour 1/2 cup sherry over bottom layer; press 1/2 cup almonds into cake and spread 1/2 cup apple jelly over almonds. Cover with remaining layer, and repeat procedure with remaining sherry, almonds, and jelly.
Spread Creamy Custard Filling over entire cake; frost with whipped cream just before serving.