Step 1: Preheat your oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan, or line it with parchment paper for easy removal.
Step 2: In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.
Step 3: In a separate large bowl, combine the melted butter and granulated sugar. Stir until well combined.
Step 4: Beat in the egg and vanilla extract until the mixture is smooth and slightly pale.
Step 5: Stir in the mashed bananas and the well-drained crushed pineapple until evenly distributed.
Step 6: Gradually add the dry ingredients to the wet ingredients, folding gently with a spatula just until combined. Be careful not to overmix, as this can make the bread tough.
Step 7: Pour the batter into the prepared loaf pan and spread it evenly.
Step 8: Bake for 60-65 minutes, or until a wooden skewer inserted into the center comes out clean. If the top is browning too quickly, tent with foil for the last 15 minutes.
Step 9: Allow the bread to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely before slicing.