Makes about 22 biscotti (3/4-inch-wide cookies)
1 cup unsalted pistachio nuts
1 cup granulated sugar
2 teaspoons baking powder
2 cups plus 2 tablespoons all-purpose flour
2 large eggs, plus 1 egg, lightly beaten, for brushing tops of loaves
2 tablespoons pure vanilla extract
3/4 cup dried tart cherries
Position rack in the center of the oven and preheat to 350 degrees. Line a large baking sheet with parchment paper.
Place pistachios in a single layer on a baking sheet and toast in the 350-degree oven for 8 to 10 minutes, or until just golden and aromatic. Remove and set aside.
In a large bowl, hand mix toasted pistachios, sugar, baking powder and flour.
In a small bowl, whisk eggs and vanilla extract until well blended. Add to the flour mixture. Toss in the cherries. Stir a few times. Work the batter together with lightly floured hands. The mixture will be sticky, but persevere. Keep squeezing the batter with your hands, until a dough starts to form. Once the dough is firm, form a ball. Divide the ball into 2 equal pieces.
On a lightly floured surface, place 1 piece of dough and using your hands, roll into a log shape that is approximately 10 inches long, 3 inches wide and 3/4 of an inch high. If it's sticky, simply dust your palms with more flour. Repeat with remaining three pieces of dough. Place two logs per baking sheet. Brush loaves all over with 1 lightly beaten egg.
Bake for 40 minutes, turning the pan around halfway through, or until the tops of the loaves are shiny and deep golden. Cool on a rack for about 20 minutes before slicing. Place a loaf on a cutting board. Using a large serrated knife, cut 3/4-inch-thick slices, either straight or on the diagonal. Use a sawing motion to prevent crumbling. Each loaf should yield 9 to 11 cookies. If the cookie is crumbling, then let it cool a few more minutes. Don't let it rest too long, however, or it could become too hard to slice.
Place slices on their sides back on to the baking sheets. Reduce oven temperature to 200 degrees, and bake biscotti for 20 minutes, until toasted and crisp. If you desire, you can turn off the oven and let the biscotti stay for up to an hour. The longer they stay in the oven, the harder they will become. Remove from oven and cool completely before storing in an airtight container, preferably a tin, which helps keep them crisp. Stored properly, biscotti will last up to a month.