Cake: Preheat oven to 180 degrees C. Grease and flour two 23cm cake tins.
In a medium bowl mix together the flour, baking powder, salt and ground walnuts. Set aside. In a small bowl whip the cream until stiff peaks form. Set aside.
In a large bowl combine the sugar, eggs and vanilla. Beat 5 minutes at highest speed of an electric mixer. Fold in the flour mixture alternately with whipped cream.
Pour batter into prepared cake tins. Bake in the preheated oven for 25 to 30 minutes, or until a toothpick inserted into the centre of the cake comes out clean. Let cool in the cake tin for 15 minutes then turn out onto a wire rack and cool completely.
Frosting: In a large bowl combine cream cheese, sugar, salt and vanilla. Beat until smooth. In a separate small bowl, whip 1 1/2 cups whipping cream until stiff peaks form. Fold whipped cream into cream cheese mixture.
To Assemble: Split each layer in half horizontally to form 4 layers. Place 1 layer on serving plate then spread with 1/2 cup of frosting. Top with second layer then spread with 1/2 cup jam. Top with 3rd layer then spread with 1/2 cup frosting. Top with remaining cake layer. Frost the sides of cake reserving about 1 cup for decorating. Spread remaining jam on top of the cake. Using a pastry bag and a star tip, pipe reserved icing in a lattice design on the top of cake, pipe border around top and bottom edges of cake. Store in refrigerator.