1 1/2 cups all-purpose flour
1 cup unprocessed wheat bran
1 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon ground allspice
1/4 teaspoon salt
1 cup bananas, mashed, very ripe (about 3 small bananas)
1/2 cup honey
1/3 cup sour cream
1 large egg
6 tablespoons unsalted butter, melted
1 teaspoon vanilla extract
3/4 cup walnuts, toasted and chopped