Preheat oven to 350 degrees. Combine bananas, apples, sugars and water. Stir in melted butter. In another bowl, whisk flour, baking soda, baking powder and salt. Stir into banana mixture. Transfer to a greased and floured 9x5-in. loaf pan. Bake until a toothpick inserted in the center comes out clean, 50-60 minutes. Cool in the pan for 10 minutes before removing to a wire rack to cool completely.
Preheat oven to 350 degrees. Combine bananas, apples, sugars and water. Stir in melted butter. In another bowl, whisk flour, baking soda, baking powder and salt. Stir into banana mixture. Transfer to a greased and floured 9x5-in. loaf pan. Bake until a toothpick inserted in the center comes out clean, 50-60 minutes. Cool in the pan for 10 minutes before removing to a wire rack to cool completely.
Mashed bananas and chopped apples carry high water content that frequently turns quick breads into dense, heavy bricks. Ripe bananas release free liquid as they break down during baking. Peeling and chopping the apples uniformly ensures they soften without pooling water inside the crumb. Toss the fruit pieces thoroughly with the sugars to draw out excess moisture before combining them with the fats and dry goods.
Measuring flour by volume often packs too much dense starch into the bowl, resulting in dry batter. Whisking the all-purpose flour alongside the chemical leaveners distributes the baking soda and baking powder evenly. Combine the wet and dry components just until moistened. Overworking the gluten creates tough tunnels throughout the interior instead of a tender structure.
Coating the 9x5-inch loaf pan with a thorough layer of solid shortening and flour prevents the sticky caramel topping from bonding to the metal. Bake at 350 degrees Fahrenheit until a wooden pick inserted into the center emerges clean. Let the loaf rest inside the pan for precisely 10 minutes to allow the starches to set before transferring it to a wire cooling rack.