Preheat your oven to 350°F (180°C) and grease and flour a 9x13 inch baking pan.
In a large bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg and ginger
In a separate bowl, mix together the pumpkin puree, grated carrots, vegetable oil, granulated sugar, brown sugar, eggs, and vanilla extract until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Pour the batter into the prepared baking pan and smooth the top with a spatula.
Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.
Allow the cake to cool before frosting.