To prepare the cake, coat 2 8-inch round cake pans with cooking spray. Line the bottoms with wax paper. Coat wax paper with cooking spray. Dust each pan with 11/2 tsp flour.
Place granulated sugar and 1/4 cup butter in a large bowl; beat with a mixer at medium speed until well blended (about 3 minutes). Add eggs, 1 at a time, beating well after each addition.
Lightly spoon 13/4 cups flour into dry measuring cups, and level with a knife. Combine flour, baking powder, and 1/2 teaspoon salt, stirring well with a whisk.
Combine buttermilk, banana, and 1 tsp vanilla in a pyrex measuring cup.
Beginning and ending with the flour mixture, add the flour mixture and buttermilk mixture alternately to the sugar mixture. Mix after each addition just until blended. Pour batter into prepared pans.
Bake cake at 350 for 25 minutes or until wooden pick inserted in center comes out clean. Cool in pans 10 minutes on a wire rack; remove from pans. Peel off wax paper. Cool layers completely on wire rack.
To prepare frosting, combine cream cheese, 2 tbs butter, rind, 1/2 tsp vanilla, and dash of salt in a large bowl. Beat with a mixer at high speed until fluffy. Gradually add powdered sugar; beat at low speed just until blended. Do not overbeat.
Place 1 cake layer on a plate and spread with 1/3 cup frosting. Arrange raspberries in a single layer over frosting and top with remaining cake layer. Spread remaining frosting over top and sides of cake. Store cake loosely covered in refrigerator. Garnish with fresh raspberries, if desired.