Mix flour, sugar, baking powder. baking soda and salt in large bowl.
Add to flour mixture banana, buttermilk, shortening, eggs and vanilla.Beat on medium speed 3 minutes.
Pour evenly into prepared pans.
Bake at 350 degrees for 30 minutes.
Cool 10 minutes and remove from pans.
Finish cooling completely.
Using a long serrated knife, cut each layer of cake in half. Set aside.
SWEETENED WHIPPED CREAM:
In a chilled mixing bowl (clean and free of any grease) combine 1 cup whipping cream and 1 tablespoon sugar. Beat with chilled beaters of mixer on low to medium speed until soft peaks form (tips will curl). Do not over beat.
Divide whipped cream in half. Fold strawberries into one half and drained pineapple into the other half.
Heat and stir fudge over low heat until just warm.
Place 1st layer of cake on platter, top with strawberry cream spreading to the edge.
Place 2nd layer on top of 1st. Spread 1/2 of warm fudge,let some of it drizzle down the sides. Sprinkle with 1/2 of peanuts.
Place 3rd layer on top of 2nd. Top with pineapple cream spreading to edge.
Place 4th layer on top of 3rd. Spread remaining warm fudge over, again letting some drizzle down sides. Sprinkle with remaining peanuts. Garnish with last banana sliced.