01 - Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan or line with parchment paper.
02 - Whisk together flour, baking soda, baking powder, salt, cinnamon, nutmeg, and ginger in a large bowl.
03 - Beat eggs in a separate bowl, then add mashed bananas, oil, brown sugar, granulated sugar, and vanilla. Mix until combined.
04 - Stir grated carrots into the wet mixture.
05 - Add wet ingredients to dry ingredients and mix gently until just combined. Avoid overmixing.
06 - Fold in chopped walnuts if desired.
07 - Pour batter into prepared loaf pan and spread evenly.
08 - Bake for 50-60 minutes until a toothpick inserted in center comes out clean.
09 - Cool in pan for 10 minutes, then transfer to wire rack to cool completely before slicing.