Cake: Combine sugar and next 4 ingredients in a large bowl; stir well using a wire whisk. Combine flour and next 4 ingredients; add to liquid mixture, folding just until blended. Stir in walnuts. Spread batter into two greased and floured 23 cm cakepans; bake at 190ºC for 20 to 25 minutes or until a wooden pick inserted in center comes out clean. Cool in pans 5 minutes; remove from pans, and let cool completely on wire racks. Measure out 0.75 cup Bavarian Cream Frosting; gently stir in pineapple. To assemble, place one cake layer on serving platter; spread pineapple mixture over layer. Top with second cake layer; spread remaining Bavarian Cream Frosting on top and sides of cake. Cover with BAVARIAN CREAM FROSTING: Combine gelatin and water in a small bowl; let stand 1 minute. Combine milk, sugar, and gelatin mixture in a small saucepan; cook over medium heat, stirring constantly, until sugar is melted and gelatin is dissolved (coat spoon with mixture and make sure it is no longer grainy). Remove from heat and cool to room temperature; stir in sour cream. Cover with plastic wrap and refrigerate until mixture is consistency of unbeaten egg whites, about 30 minutes. Fold one-fourth whipped cream into chilled mixture until smooth; fold in remaining whipped cream. Cover and refrigerate until spreading about 5 cups Garnish with chopped walnuts on top and surround base of cake with walnut halves. SOURCE: Cafe Southern Living 5-Star Dining