Preheat the oven to 350°F (175°C) and grease a loaf pan with butter or non-stick spray to prevent the apple bread from sticking.

Mix the dry ingredients in a large bowl: whisk together the flour, granulated sugar, brown sugar, cinnamon, baking soda, baking powder, salt, and nutmeg until well combined.

Beat the eggs in a separate bowl, then add the melted butter and chopped apple to incorporate moisture and flavor into the mixture.

Combine the wet and dry ingredients gently, stirring until there are no dry spots left. Fold in the toasted walnuts or pecans if you're using them.

Pour the batter into the prepared loaf pan, making sure it's evenly distributed.

Sprinkle additional granulated sugar on top of the batter if desired.

Bake in the preheated oven for about 55 minutes, or until a toothpick inserted comes out clean.

Cool the apple bread in the pan for 10 minutes before transferring it to a wire rack to cool completely.