Adapted from Susan Russo's Recipe found on NPR
~from Savoring Time in the Kitchen
Makes about 36 biscotti (3/4-inch-wide cookies)
3 cups unsalted whole almonds (I buy the large bags at Sam's Club)
1 cup granulated sugar
1 cup brown sugar (I used dark brown)
1/2 teaspoon ground cinnamon
2 teaspoons baking powder
2 1/2 cups all-purpose flour (I used 2 cups of all purpose and 1/2 cup of whole wheat flour)
3 jumbo eggs (or 4 large eggs), plus 1 egg, lightly beaten, for brushing tops of loaves
1 teaspoon pure vanilla extract
Zest of 2 oranges (2 teaspoons)
Place the oven racks in the upper and lower thirds of the oven and preheat to 350 degrees. Line 2 large baking sheets with parchment paper or silicone mats.
Arrange almonds in a single layer on a baking sheet and toast in the 350-degree oven for 10 minutes. Remove and set aside to cool.
In a large bowl, mix toasted almonds, sugars, cinnamon, baking powder and flours.
In a small bowl, whisk the eggs, then add the vanilla and orange zest and whisk until well blended. Add to the flour mixture and stir a few times. Place 1/4 cup of flour near the work bowl and start to work the batter together with floured hands. The mixture will be sticky, but keep squeezing the batter with your hands until a dough starts to form, adding a little more flour at a time if it is too sticky. You do not want to get the dough too dry. Once the dough is firm enough, form a ball. Divide the ball into 4 equal pieces.
On a lightly floured surface, place 1 piece of the dough, and using your hands, roll into a log shape that is approximately 8 inches long, 2 inches wide and 3/4 of an inch high. If it's sticky, simply dust your hands with more flour. Repeat with remaining 3 pieces of dough. Place 2 logs on each baking sheet. Brush the tops and sides of the logs with the lightly beaten egg.
Bake for 40 minutes, rotating pans halfway through, until the tops of the loaves are shiny and deep golden. Turn oven off and cool on a rack for 20 minutes before slicing.
Place a loaf on a cutting board. Using a large, sharp, serrated knife, cut 3/4-inch-thick slices, either straight across or on the diagonal. Use a sawing motion to prevent crumbling. Each loaf should yield 9 to 11 cookies.
Place slices on their sides back onto the baking sheets. Place in the still warm oven with the temperature off and the door closed for about 30. The longer they stay in the oven, the harder they will become. Remove from oven and cool completely before storing in an airtight container, preferably a tin, which helps keep them crisp. Stored properly, biscotti will last up to a month.