Preheat your oven to 350°F (175°C) and grease a 9x5-inch (23x13 cm) loaf pan.

In a medium-sized bowl, whisk together the flour, baking powder, baking soda, salt, 1 teaspoon ground cinnamon, ground ginger and ground nutmeg. Set it aside.

In a small bowl add apple, brown sugar and ½ teaspoon cinnamon and mix well and set aside.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy. You can use an electric mixer for this step.

Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.

Then add milk and sourdough starter/ discard and mix well.

Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Do not overmix.

Gently fold in the chopped apple-cinnamon brown sugar mixture ( reserve 2 tablespoons apple mixture for the topping).

Pour the batter into the prepared loaf pan and spread it evenly.

Bake in the preheated oven for about 45-50 minutes or until a toothpick or cake tester inserted into the center comes out clean, with a few moist crumbs attached.

Remove the apple loaf from the oven and let it cool in the pan for about 10-15 minutes. Then, transfer it to a wire rack to cool completely.

Once the apple loaf has cooled, you can slice it and enjoy!