1 stick (1/2 cup, or 8 tablespoons) unsalted butter, softened
3/4 cup sugar
2 large eggs
1 teaspoon pure vanilla extract
1 cup pistachios, shells discarded, toasted
1 cup dried cranberries
2 ounces white chocolate, melted
Heat oven to 325°. In a small bowl, whisk together flour, baking powder, baking soda, and salt. In the bowl of a standing mixer, beat butter with sugar until light and fluffy. Beat in eggs one at a time. Add vanilla. Lower speed and beat in dry ingredients. Stir in pistachios and cranberries by hand.
Line a baking sheet with parchment paper or Silpat. Form dough into two logs, 14 inches long by 4 inches wide by 1-1/2 inches high.
Bake until golden, about 30 minutes. Transfer baking sheet to a rack; let cool about 5 minutes. Using a serrated knife, slice logs on the diagonal into 1/2-inch-thick pieces.
Arrange slices on a lined baking sheet and bake about 8 minutes per side. Transfer biscotti to a rack and cool completely. Drizzle with melted white chocolate. Refrigerate until set, about 10 minutes.