Preheat your oven to 350°F (175°C). Line a large baking sheet with a piece of parchment paper and set it aside.
In a small bowl, combine the granulated sugar and fresh orange zest. Use your fingertips to rub the zest into the sugar for about a minute. The sugar will become beautifully fragrant, slightly moist, and take on a pale orange tint—this maximizes the citrus flavor!
In a large mixing bowl, whisk together the all-purpose flour, baking powder, salt, and the orange-infused sugar.
In a separate bowl, lightly beat the eggs, then whisk in the fresh orange juice and vanilla extract.
Pour the wet ingredients into the dry flour mixture. Use a wooden spoon to mix until a dense, slightly sticky dough begins to come together.
Fold in the dried cranberries, using your hands to gently knead the dough if necessary so the fruit is evenly dispersed.
Turn the dough out onto a floured surface. Divide it into two equal halves. Shape each half into a log measuring roughly 9 inches long by 2.5 inches wide. Place them on the prepared baking sheet, leaving room for them to expand.
Bake for 25 minutes until the logs feel firm to the touch and are lightly golden. Remove from the oven and let them cool on the pan for 10 to 15 minutes. Reduce your oven temperature to 325°F (165°C).
Transfer the cooled logs to a cutting board. Using a sharp serrated knife, gently saw them on a diagonal into 3/4-inch thick slices.
Place the biscotti slices cut-side down on the baking sheet. Bake for 8-10 minutes, flip them over, and bake for a final 8-10 minutes until lightly toasted and completely dry. Cool on a wire rack before storing in an airtight container!