Sift flour, sugar, baking soda, cinnamon and salt into a bowl. In another bowl, stir or whisk the bananas, pineapple, oil, eggs and vanilla until combined. Do not use an electric mixer. Pour into the dry mixture and fold together with a large spatula just until smooth. Do not beat. Fold in pecans. Spread evenly into the pans.
Bake until cake springs back when pressed in the center, 30 to 35 minutes. Transfer cakes to wire racks and cool for 10 minutes. Invert cakes onto racks (remove the parchment paper now if using). Turn right side up and cool completely.
Place 1 cake layer upside down on a serving platter. Spread with about 2/3 cup of icing. Top with the second layer, right side up. Spread reaming icing over the top and sides of the cake. The cake can be prepared up to 1 day ahead and stored, uncovered in the refrigerator. Let stand at room temperature 1 hour before serving.
Makes 12 servings