Preheat your oven to 350°F. Line a baking sheet with parchment paper and set it aside. This will help ensure your biscotti don’t stick.
In a large mixing bowl, combine all-purpose flour, baking soda, salt, and sugar. Stir well to mix the dry ingredients thoroughly.
Using a wooden spoon or rubber spatula, add the lightly beaten eggs, vanilla extract, orange zest, and pistachios to the dry ingredients. Mix until everything is well combined, forming a thick, sticky dough.
Turn the dough out onto a lightly floured work surface. Divide the dough into four equal pieces. Roll each piece into a log about 12 inches long and place them on the prepared baking sheet.
Flatten each log slightly with your hands. Bake in your preheated oven for about 12 minutes, or until they feel firm to the touch but are not golden brown. They should be about three-quarters baked.
Once baked, remove the logs from the oven and allow them to cool completely on a wire rack.
After they have cooled, use a sharp serrated knife to cut the logs into ⅓ inch thick slices. Be careful not to squish the cookies while cutting.
Lay the sliced biscotti back on the parchment-lined baking sheet, cut side up. Bake again for another 10 to 15 minutes, or until they are lightly toasted and crisp.
Once baked, remove from the oven and allow to cool completely. As they cool, they will become even crisper.
Enjoy your freshly baked Orange Pistachio Biscotti with coffee or tea!