Heat the oven to 350°F. Grease a 9×5-inch loaf pan. Whisk the flour, sugar, baking powder, and salt together in a large bowl.
Mix the melted butter and bananas together in a medium bowl. Beat in the eggs and vanilla until well combined. Stir the wet ingredients into the dry ingredients just enough to combine everything. Gently fold in the candied ginger.
Pour the batter into the prepared pan. Bake for 50 to 60 minutes, until the bread is golden brown and a toothpick inserted in the center of the bread comes out almost entirely clean. Cool in the pan on a rack for 15 minutes, then carefully turn it upside down to release the loaf. Serve warm or at room temperature. Or wrap and keep at room temperature for up to a couple of days.