For the cake: Preheat the oven to 350°.

Whisk together the flour, sugar, cinnamon, salt, baking soda, and baking powder in a large bowl. Stir in the oil, eggs, vanilla, and pineapple until evenly combined. Mash the bananas then add to the bowl with the pecans. Stir to combine.

Spray 2 (8-inch) round baking pans with nonstick baking spray (or, butter and flour the pans). Divide the batter evenly between the prepared pans. Bake in the preheated oven until a wooden pick inserted in the center comes out with just a few small crumbs, 33 to 37 minutes. Cool the cakes in the pans on a wire rack for 10 minutes. Invert the cakes onto the wire rack and cool completely, about 1 hour.

For the frosting: Beat the butter and cream cheese in a stand mixer fitted with the paddle attachment on medium until smooth and creamy, 2 to 3 minutes. Add the powdered sugar then mix at low speed just until combined. Scrape the sides and bottom of the bowl. Add the vanilla and salt. Beat frosting on medium-high speed until light and fluffy, about 2 minutes.

Place one of the cake layers on a serving plate and top with about 1 cup of the frosting, spreading evenly to the edge. Top with the second cake layer. Spread the remaining frosting on the top and sides of the cake.

To decorate the cake: Press the pecan halves along the base of the cake and around the top of the cake to create a ring. Slice and serve.