In a medium bowl, whisk together the flour, baking powder, ginger and baking soda; set aside.
In a large bowl, whisk together the brown sugar, oil, honey, eggs and vanilla extract. Add the flour mixture and stir with a rubber spatula until no flour remains. Fold in the carrots, zucchini and walnuts.
Spread the batter into an ungreased 9x13-inch pan. Bake until a toothpick inserted in the center comes out clean, about 25 minutes. Place the pan on a wire rack and cool completely.
Using an electric mixer, beat the cream cheese, powdered sugar and vanilla extract on medium speed until smooth and creamy, about 3 minutes. Spread evenly over the cooled bars. The bars can be kept in an airtight container at room temperature or in the refrigerator for up to 3 days.
The ginger flavor in these is fairly pronounced, so if you don't like ginger feel free to omit it or substitute cinnamon. You can also use walnuts in place of the pecans, or really any other nut that you like.