1 1/2 cups fruit and vegetable pulp leftover from a juicer (We used 1 cup berry/apple and 1/2 cup carrot, but any combination will work here. See Cook's Note)
Preheat the oven to 350 degrees F; spray a 9-by 5-inch loaf pan with nonstick cooking spray (see Cook's Note).
In a medium bowl, whisk together the flour, baking powder, cinnamon, baking soda, salt and cardamom if using.
In another large bowl, whisk together the light brown sugar, vegetable oil, granulated sugar, vanilla and eggs. Add the dry ingredients to the wet in 2 additions, folding together until just combined. Fold in the fruit and vegetable pulp.
Pour into the prepared pan and bake until a toothpick inserted in the center comes out clean, 50 minutes to 1 hour. Set aside until the pan is cool enough to handle, then unmold the bread onto a wire rack to cool completely before slicing.
If you don't have a juicer, substitute 1 1/2 cups of any combination of finely grated fruit and vegetables for the pulp. Alternatively, this can be made in a muffin tin. Just reduce the baking time to about 20 minutes, or until a toothpick inserted in the center of one comes out clean.