Preparing the Batter
1-Preheat oven to 350°F (175°C) and grease: Preheat oven to 350°F (175°C) and grease a 9-inch cake pan.
2-In a medium bowl, whisk together flour,: In a medium bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and ginger.
3-In a larger bowl, beat together the: In a larger bowl, beat together the oil and brown sugar until combined.
4-Add eggs one at a time, mixing: Add eggs one at a time, mixing well after each addition. Stir in vanilla extract.
5-Gently fold in the grated zucchini (drained): Gently fold in the grated zucchini (drained) and mashed sweet potato until evenly distributed. Do not overmix.

Baking the Cake
6-Gradually add the dry ingredients to the: Gradually add the dry ingredients to the wet mixture, stirring just until combined (no flour streaks). Avoid overmixing.
7-Pour batter into the prepared pan and: Pour batter into the prepared pan and smooth the top.
8-Bake for 35-40 minutes, until a toothpick: Bake for 35-40 minutes, until a toothpick inserted comes out with a few moist crumbs and edges pull slightly from the pan.
9-Let cake cool in the pan for: Let cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.