Modified from website
1 3/4 cups flour
1/2 cup sugar
1 tsp baking powder
1/4 tsp salt
1/2 cup mashed banana
1 tbsp vegetable oil
1 tsp vanilla
1 egg (they say large, I use extra large)
1/2 cup chopped walnuts
Preheat oven to 350. Line baking sheet of parchment paper and lightly grease. Set aside.
In large bowl, whisk together flour, sugar, baking powder and salt. Set aside. In a separate bowl, whisk together the mashed banana, oil, vanilla and egg until smooth. Pour into dry ingredients and stir/knead until mixed. It will be very sticky. Mix in nuts. I find my hands work best.
Transfer to a floured surface and roll into logs and then flatten into 1/2 inch thick logs. Again my hands are best, well floured.
Bake for 23 minutes (mine took a little longer, but mine were pretty thick and long). Remove from the oven, lower to 250 degrees and let biscotti cool for 10 minutes. Slice each into even slices and place on baking side, sliced side down. Bake for 15 minutes, flip over and continue for another 15 minutes on the second side. (Again might took a little longer). Remove from the oven and let cool completely on a wire rack and let cool and dry out.