Preheat the oven to 350F.
Cream together the butter and the sugars in a mixing bowl until well combined.
Add the vanilla extract, add the eggs one by one, and add the orange juice, mixing until just combined in between each addition.
In a separate bowl, whisk together the flour, cinnamon, and orange zest.
Add the dry ingredients to the butter and egg mixture and mix until combined.
On a baking sheet with waxed paper or a silicone mat, spread the batter into a rectangle of about 4-6 inches in width and about ¾-inch thickness.
Bake the batter at 350F for 35-40 minutes until the cookie becomes firm and the top springs back when pressed lightly with a finger.
Allow the cookie to cool for at least 60 minutes before cutting the large cookie into thin slices of about ½-inch width.
Preheat the oven to 325F.
Place the slices onto the baking sheet with one of the sliced sides facing upwards. Bake at 325F for 15-20 minutes. The biscotti should be firm and slightly dry.