Preheat oven to 350°F (175°C). Grease and flour three 9-inch round cake pans.
Mix dry ingredients: In a large bowl, whisk together flour, sugar, baking soda, cinnamon, and salt.
Add wet ingredients: Stir in eggs, oil, and vanilla until combined.
Add fruit & nuts: Fold in pineapple (with juice), mashed bananas, and pecans. Mix until just combined.
Bake: Divide batter evenly between pans. Bake for 25–30 minutes, or until a toothpick comes out clean.
Cool: Let cakes cool in pans for 10 minutes, then turn out onto wire racks to cool completely.
Make frosting: Beat cream cheese and butter until smooth. Gradually add powdered sugar and vanilla, beating until creamy.
Assemble cake: Place one cake layer on a plate, spread frosting evenly. Repeat with remaining layers, then frost the top and sides.
Garnish: Sprinkle with extra pecans or decorative toppings if desired.