Step by step

1. Position an oven rack in the center of the oven and preheat the oven to 180ºC. Cut a piece of parchment paper long enough to fit the bottom and up the ends of the pan with a 5 cm overhang on each end. Grease the pan with melted butter. Fit the parchment into the pan and grease the bottom and ends of the parchment. (The excess parchment on each end makes it easy to lift the loaf out of the pan once baked.)

2. In a large bowl, sift together the flour, baking powder, salt, cinnamon, baking soda, and nutmeg. Set aside.

3. Place the crystalized ginger and walnuts into the blender, and pulse 5-7 times, or until they are the consistency of a rough chop. Pour the chopped walnuts and ginger into the bowl with dry ingredients.

4. Place the bananas, sugar, butter, and eggs in the blender. Blend on speed 3 until smooth and well combined, about 20 seconds. Fold the banana mixture into the dry ingredients, add the flax seeds, and fold in just until combined. Transfer the batter to the prepared pan and sprinkle a bit more crystalized ginger and crushed walnuts over the top.

5. Bake the quick bread until deeply brown on the top and sides, and a cake tester comes away clean when inserted into the center of the bread, about 50 minutes. Transfer to a wire rack and cool in the pan for 30 minutes. Use the parchment overhanging the sides to lift the bread from the pan. Cool on the rack. Cut slices for serving. Toast the slices, if desired. Wrap the loaf lightly in a plastic bread bag and store at room temperature for 2 days. The loaf can be frozen for up to 1 month.