Heat the oven to 350 °F. Line a large baking sheet with parchment paper.
Whisk the flour, baking powder and salt in a medium bowl. In a large bowl, whisk the sugar, eggs and vanilla until pale and slightly thickened, about 2 minutes.
Stir the dry ingredients into the egg mixture until just combined, then fold in the cranberries and pistachios. The dough will be sticky.
With damp hands, shape the dough into two 12-inch logs, about 2 inches wide, on the baking sheet, 3 inches apart. Bake 25-30 minutes, until firm and lightly golden. Cool on the sheet for 15 minutes.
Reduce the oven to 325 °F. Move each log to a cutting board and slice diagonally into 1/2-inch slices. Arrange the slices cut-side down on the baking sheet.
Bake 10 minutes, turn the slices over, then bake 8-10 minutes more, until dry and crisp. Cool completely on a wire rack. Store airtight for up to 2 weeks.