Preheat the oven: Preheat your oven to 350°F (175°C). Grease and flour a 9×9-inch square pan or a similar-sized baking dish.

1. Mix dry ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, ginger (if using), and salt.
2. Combine wet ingredients: In a large bowl, combine the applesauce, pumpkin puree, brown sugar, oil, eggs, and vanilla extract. Whisk until smooth and fully combined.
3. Combine wet and dry ingredients: Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix.
4. Add nuts (optional): If you’re using nuts, fold them into the batter gently.
5. Fill the pan: Pour the batter into the prepared pan and spread it evenly.
6. Bake: Bake for 30-35 minutes, or until a toothpick inserted into the center of the cake comes out clean.
7. Cool: Let the cake cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.
8. Finish: Once cooled, dust the top with powdered sugar for an added touch of sweetness, if desired. Slice and serve!