Preheat oven to 350 degrees F. Butter and flour a 9x5-inch loaf pan. Set aside.
In the bowl of a stand mixer fitted with paddle attachment, cream together butter and sugar until fluffy. Add eggs and vanilla. Mix until combined.
Add mashed bananas and shredded zucchini. Mix until combined. Scrape down bowl as needed.
In a large bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, nutmeg, ginger, cardamom, and turmeric. Add to mixing bowl. Mix on low speed until fully combined and there are no longer any dry streaks of flour.
Transfer batter to prepared loaf pan. Bake for 60-70 minutes until bread is golden brown and toothpick inserted in center of bread comes out clean. Let bread cool in pan for 10-15 minutes before unmolding. Allow bread to cool to room temperature on a wire rack.