Step 1: Prepare the Apple Pie Filling

• In a small skillet, melt 1 tablespoon of butter over medium heat.
• Add the diced apple, brown sugar, cinnamon, nutmeg, and a pinch of salt. Stir to combine and cook for 4-5 minutes until the apples soften and begin to caramelize.
• Remove from heat and set aside to cool slightly while you prepare the banana bread batter.

Step 2: Make the Banana Bread Batter

• Preheat your oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan, or line it with parchment paper.
• In a large mixing bowl, mash the ripe bananas with a fork until smooth.
• Add the melted butter, brown sugar, eggs, and vanilla extract. Stir to combine until everything is well incorporated.
• In a separate bowl, whisk together the flour, baking soda, salt, cinnamon, and nutmeg.
• Gradually add the dry ingredients to the wet ingredients, mixing just until combined.
• Add the buttermilk (or milk with lemon juice) and stir until the batter is smooth and thick.
• Fold in the chopped nuts, if using.

Step 3: Fold in the Apple Pie Filling

• Gently fold the apple pie filling into the banana bread batter, being careful not to overmix. You want the apples to be evenly distributed throughout the batter but not mushy.

Step 4: Pour the Batter into the Loaf Pan

• Pour the batter into the prepared loaf pan and spread it out evenly.
• In a small bowl, combine the granulated sugar and cinnamon. Sprinkle this mixture over the top of the batter to create a nice sugary crust.

Step 5: Bake the Banana Bread

• Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center of the bread comes out clean (with just a few crumbs).
• If the top begins to brown too quickly, cover it loosely with aluminum foil and continue baking.

Step 6: Cool and Slice

• Allow the banana bread to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.
• Once cooled, slice and enjoy!