This recipe is tried and true from Smitten Kitchen. She says it will yield about 45 but it depends on how thinly you slice them:
- 3 ¼ cups all purpose flour
- 1 Tbs baking powder
- 1/3 tsp salt
- 1 ½ cups sugar
- 10 Tbs (1 ¼ sticks) unsalted butter, melted
- 3 large eggs
- 1 Tbs vanilla extract
- 1 Tbs orange liqueur (or 1 tsp almond extract)
- 1 Tbs orange zest
- 1 cup whole almonds, toasted (coarsely chopped or sliced almonds)
- 1 large egg white to brush the tops
Position rack in center of oven and preheat to 350°F. Line baking sheet with parchment paper. Sift flour, baking powder and salt into medium bowl. Mix sugar, melted butter, 3 eggs, vanilla extract, liquer and zest in large bowl. Add flour mixture to egg mixture and stir with wooden spoon until well blended. Mix in almonds.
Divide dough in half. Using floured hands, shape each dough half into 13 1/2-inch-long, 2 1/2-inch-wide log. Transfer both logs to prepared baking sheet, spacing apart. Whisk egg white in small bowl until foamy; brush over top and sides of each dough log.
Bake logs until golden brown (logs will spread), about 30 minutes. Cool logs completely on sheet on rack, about 25 minutes. Maintain oven temperature.
Transfer logs to work surface; discard parchment paper. Using serrated knife, cut logs on diagonal into ½” wide slices. Arrange slices, cut side down, on same baking sheet. Bake 12 minutes. Turn biscotti over; bake until just beginning to color, about 8 minutes. Transfer to rack and cool.
You can make these one week ahead; store in airtight container at room temperature.