How to Make It
Preheat oven to 350°F. Coat 2 (9- x 5-inch) loaf pans with cooking spray.
Combine bananas, yogurt, soy milk, oil, and vanilla in a food processor and process until smooth, about 1 minute.
Whisk together flour, sugar, baking powder, baking soda, cinnamon, and salt in a large bowl. Add banana mixture to flour mixture; stir well to thoroughly combine. Stir in walnuts. Pour batter evenly into prepared loaf pans.
Bake on middle rack until a wooden pick inserted in center of loaves comes out clean, 40 to 45 minutes. Remove from oven and cool in pans 10 minutes. Remove from pans and cool 10 minutes before slicing.