Heat oven to 350°F (176ºC) with rack set in middle position. Coat an 8½ × 4½-inch loaf pan with nonstick spray. Line pan with parchment paper, leaving a 2-inch overhang on two sides; coat paper with nonstick spray.
Whisk together 2 cups (250g) flour, 1½ teaspoons cinnamon, 1 teaspoon ginger, 1 teaspoon baking soda, and ½ teaspoon salt.
In a separate bowl, mash 2 bananas until very smooth (should get 1 cup or 234g). Add 2 eggs, ½ cup honey, ½ cup (120g) yogurt, ¼ cup oil and 1 tablespoon vanilla; whisk until smooth.
Add flour mixture to banana mixture and mix until combined. Add ⅔ cup chopped walnuts and mix just until combined. Scrape batter into prepared pan, smooth top, and sprinkle 2 tablespoons turbinado sugar over to.
Bake bread until dark brown on top and a toothpick inserted in the center comes out mostly clean with a few moist crumbs, 55–60 minutes.
Let bread cool in pan on wire rack 10 minutes. Turn bread out and let cool completely on wire rack.