Mix the dough:
In a small bowl, combine the currants, raisins, brandy, lemon zest, and ginger and let stand for 20 min. With an electric mixer fitted with the paddle attachment, combine the flour, granulated sugar, cornmeal, baking powder, and salt. In a small bowl, whisk together the eggs, egg yolks, and vanilla. With the mixer on low speed, add the egg mixture to the dry ingredients until just combined and the dough looks crumbly. Take care not to overmix. Add the fruit mixture and the pine nuts, mixing just until the dough comes together (bring the dough together with your hands if it’s a bit stiff). Let the dough rest for 15 to 30 min. before shaping.
Meanwhile, position oven racks in the middle and top of the oven and heat the oven to 350°F.
Shape the dough and do the initial baking.
Line a large baking sheet with parchment. Cut the dough in half. Using as little flour as possible on the work surface, roll each half into a log that’s 16 inches long and 2 inches wide, working out the air pockets as you go. (If you’re working ahead, wrap the logs in plastic and refrigerate them overnight). Transfer the logs to the baking sheet, setting them about 3 inches apart and patting the sides to smooth and straighten. Brush the tops and sides with the beaten egg white and sprinkle with the turbinado sugar.
Bake on the middle rack until golden brown and firm in the center, 30 to 35 min., rotating the sheet to ensure even baking. Set the sheet on a rack until the logs are cool enough to handle and so the dough won’t compress when you cut it, about 30 min.
Slice the baked loaf and bake a second time:
Reduce the oven temperature to 300°F. Line two large baking sheets with parchment. With a serrated knife, saw the logs into 1/2-inch-thick slices, cutting on the diagonal so each slice is about 6 inches long. Lay the slices flat on the baking sheets. Bake about 15 min., rotating the sheets and switching their positions as needed for even baking. Turn the biscotti over. Bake until both sides are a rich golden brown, another 10 to 15 min. Set the baking sheets on racks, letting the cookies cool and crisp completely on the sheets. If stored airtight, the biscotti will keep for about two weeks.
Photo: Scott Phillips (top photo); Amy Albert