2 1/2 teaspoons
unsalted butter, room temperature
- Preheat oven to 325*F.
- Mix flour, 1 1/2 tsp cinnamon, baking powder and salt in medium bowl to blend.
- Beat 1 cup sugar and butter in a large bowl until fluffy.
- Add 1 egg; beat well.
- Add egg yolk; beat well.
- Mix in vanilla, then dry ingredients.
- Transfer dough to work surface and divide in half.
- Shape each half into 9-inch long, 1 1/2 inch wide log.
- Transfer logs to prepared baking sheets that you have lined with parchment paper.
- Beat remaining egg in small bowl.
- Brush logs with egg.
- Bake until golden and firm to touch (dough will spread) about 50 minutes.
- Cool on sheets.
- Maintain oven temperature.
- Mix remaining 3 TBS sugar and 1 tsp cinnamon in small bowl to blend.
- Using serrated knife, cut logs into 1/2 inch wide diagonal slices.
- Place biscotti, cut side down, on baking sheets.
- Sprinkle 1/4 tsp cinnamon sugar mixture over each biscotti.
- Bake until pale golden, about 20 minutes.
- Store airtight at room temperature.