In a medium bowl, combine the flour, quick-cook oats, light brown sugar, baking powder, baking soda and salt.
In a separate small bowl, whisk together the oil, maple syrup and the egg yolk.
Pour the oil mixture into the flour mixture and mix until combined. The dough will be dry and crumbly.
Lightly whisk the egg white until it is lightly foamy. Pour the egg white into the dough, and mix together until everything is incorporated.
Line a baking sheet with parchment paper. Lightly flour your hands, and use your hands to transfer the dough onto the baking sheet. Shape the dough to form a log that is 12 inches (30 cm) long by 4 inches (10 cm) wide.
Bake for 20 minutes until it is lightly brown.
Remove the log from the oven and allow to cool for about 5 minutes, until you can handle it.
Using a serrated knife, slice the log diagonally into 12-15 biscotti slices.
Place each piece cut side down on the baking sheet, and bake for another 8-10 minutes.
Remove from the oven and allow to cool slightly before transferring to a cooling rack.