Take a break! These Italian-style, “twice-baked” cookies are meant to be dunked in your morning cup of coffee.
Spread the walnuts onto a baking sheet and toast them in a 325 degrees F oven for about 10 minutes. Slide nuts onto counter to cool, then chop coarsely and set aside.
Mix together the flour, baking powder, salt, and fennel seed; set aside. Beat eggs and sugar on high speed for 5 minutes, or until thick. Blend in vanilla and zest. Stir in the dry ingredients, then stir in nuts. Let the dough rest for 5 minutes.
Turn dough out onto a floured surface and divide in half. Using floured hands, shape into two 3x12-inch rectangles. Place rectangles onto large, greased and floured baking sheets, leaving some room between them. Brush with egg wash and bake for 40 minutes, or until golden. Remove from oven and cool on the baking sheets for 10 minutes. Reduce heat to 275 degrees F.
Slide the rectangles onto a cutting board. With a serrated knife, slice them diagonally, into ½-inch-wide pieces. Place the biscotti, standing up, onto baking sheets. Bake for 20 to 25 minutes longer. Cool on a rack before storing in an airtight container.