Preheat your oven to 350°F (175°C). Line a large baking sheet with parchment paper to prevent the dough from sticking.
In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt.
In a separate smaller bowl, lightly beat the eggs, then whisk in the fresh orange zest and vanilla extract.
Pour the wet egg mixture into the dry flour mixture. Stir with a sturdy wooden spoon until a stiff, slightly sticky dough begins to form.
Pour in the chopped pistachios and dried cranberries. Use your hands to gently knead and fold the inclusions into the dough until they are evenly distributed. The dense dough will hold them perfectly in place.
Transfer the dough to a lightly floured surface and divide it in half. Shape each half into a log about 9 inches long and 2.5 inches wide. Place the logs onto the prepared baking sheet, spacing them well apart.
Bake in the preheated oven for 25 to 30 minutes, until the logs are firm to the touch and slightly golden.
Remove from the oven and let the logs cool for exactly 10 to 15 minutes. Reduce the oven temperature to 325°F (165°C).
Move the semi-cooled logs to a cutting board. Using a sharp serrated knife, cut the logs on a slight diagonal into 3/4-inch thick slices. A gentle sawing motion will help you cut cleanly through the whole pistachios and cranberries.
Place the slices cut-side down back onto the baking sheet. Bake for 8-10 minutes, flip each biscotti over, and bake for another 8-10 minutes until lightly toasted and dry. Cool completely on a wire rack before serving.