Serve with soft, spreadable cheeses such as brie, Camembert, and cream cheese.
Heat oven to 350 degrees. Using large holes of box grater, grate zucchini and carrot into a bowl; set aside.
Butter and flour two 5-by-2 1/2-inch loaf pans or one 8 1/2-by-4 1/2-inch loaf pan; set aside. In medium-size bowl, combine flour, baking powder, baking soda, and salt; set aside.
In the bowl of an electric mixer fitted with the paddle attachment, beat butter and sugar on medium speed until pale and fluffy, about 2 minutes. Add eggs one at a time, beating until each is fully incorporated. Add vanilla, crystallized ginger, and reserved grated zucchini and carrot. Add reserved flour mixture; mix on low speed until combined. Pour batter into prepared loaf pans; smooth tops with a spatula. Bake until golden brown, about 45 minutes for small loaves, or 1 hour for large loaf. Transfer pans to wire rack to cool 5 minutes. Slide knife around sides of loaves in pans, then turn out onto rack; let cool. Loaves will keep wrapped in plastic for 3 days at room temperature or in the freezer for 2 weeks.