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 flour, cinnamon, ginger, baking soda, and salt.

In a separate bowl, mash bananas until very smooth. Add eggs, honey, yogurt, oil and vanilla; whisk until smooth.

Add flour mixture to banana mixture and mix until nearly combined but some packets of flour remain. Add walnuts and mix just until combined. Scrape batter into prepared pan, smooth top, and sprinkle 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.