Twice-baked biscotti can keep for weeks in jar. That's the theory, anyway. Mine never last that long. This recipe is an adaptation of Giulia Scarpaleggia's Tuscan Biscotti with Pistachios and White Chocolate from her blog, Jul's Kitchen. NOTE: Pre-heat the oven to 450° and then turn it down to 350° when you put the biscotti in. Line a large baking tray with parchment paper.
Separate one egg, setting the white aside in a small dish and adding the yolk to a mixing bowl along with two whole eggs. Add the sugar and whisk until light and fluffy and the sugar is largely dissolved. Stir in the vanilla.
Add the flour, baking powder and salt, and mix together. Then stir in the orange zest, hazelnuts and sour cherries.
Depending on whether you want classic large or smaller biscotti, divide the dough into two or three portions. With your hands and the use of a spatula, create loaves. The dough is sticky but the loaves form easily enough. If making two loaves, they should be about 12 x 2 inches. Whisk the egg white with a fork until it's light and foamy, and brush it over the loaves.
Place into the pre-heated oven and immediately turn the heat down to 350°. Bake for 20 to 25 minutes, until golden and firm but still with some give. Remove from the oven and let cool on the tray for about 10 minutes. Then put the loaves on a cutting board and slice about 3/4-inch thick. Lay the slices back on the baking tray and bake them for another 15 to 18 minutes. At this point they'll have browned and firmed up considerably. (Sometimes, especially if I'm making smaller biscotti, I slice them about 1/2-inch thick and bake them for a bit less time.)
Let the biscotti cool completely before storing in a jar or tin.
Hazelnut, Orange and Sour Cherry Biscotti https://urbancottagelife.com/hazelnut-sour-cherry-orange-biscotti/