Preheat oven to 350 degrees F. Spray 2 bread pans with cooking spray.
Whisk zucchini, oil, 1 cup sugar, brown sugar, eggs, and vanilla extract together in a bowl until well mixed. Combine all-purpose flour, whole wheat flour, baking soda, salt, 1 teaspoon cinnamon, and baking powder together in a separate bowl. Gradually stir flour mixture into zucchini mixture until batter is just combined; fold in plums. Pour batter into prepared pans.
Mix 1 tablespoon sugar and 1 teaspoon cinnamon together in a small bowl; sprinkle over batter.
Bake in preheated oven until a toothpick inserted into the center comes out clean, about 1 hour. Cool in the pans for 10 minutes before removing to cool completely on a wire rack.
0 servings