This is a recipe I originally made with white whole wheat flour. King Arthur changed the name and it is now called golden wheat flour. Free free to use all-purpose or a blend of all-purpose and whole wheat.
Preheat oven to 350°F. Line an 8x8 inch square metal pan with foil and spray with non-stick baking spray.
In a mixing bowl, using an electric mixer, mash the banana and then beat it until smooth. Beat in the egg, followed by the brown sugar, granulated sugar, vanilla and oil.
In a second bowl, thoroughly mix together the flour, baking soda and salt. Gradually stir flour mixture into banana mixture to make a very thick batter. Stir in the oats and pecans. Pour into the baking pan and spread evenly.
Bake on center rack for 32-35 minutes or until top appears brown. Let cool for about an hour or until completely cool. Remove from pan by lifting foil.
Transfer cake to a cutting board and with a large serrated knife, make ½ to ¾ inch thick slices cross-wise and slightly on the diagonal. Lay the cut pieces on a baking sheet and bake at 250F for about an hour, checking and turning every 20 minutes. Remove from oven and let cool & crisp. Biscotti may not be completely crisp when you take it out, but it should crisp as it cools. If not, just put it back in the oven for another 10-20 minutes.