Rich, nutty, iced maple walnut biscotti paired with a steaming mug of coffee is a classic New England favorite. I have made these biscotti with both maple extract and pure maple syrup and find that the extract lends a more robust maple flavor. If you'd rather use maple syrup, then start with 1/4 cup. You'll need to add a bit more flour, though, since the syrup will make it wetter. As for the icing, I prefer syrup.
Makes about 36 biscotti (3/4-inch-wide cookies)
2 cups unsalted walnuts
1 cup granulated sugar
1 cup light brown sugar
1/2 teaspoon ground cinnamon
2 teaspoons baking powder
2 1/2 cups all-purpose flour
2 large eggs, plus 1 egg, lightly beaten, for brushing tops of loaves
3 tablespoons maple extract
1/2 cup confectioners' sugar
3 tablespoons maple syrup
Position racks in the upper and lower thirds of the oven and preheat to 350 degrees. Line 2 large baking sheets with parchment paper.
Place walnuts in a single layer on a baking sheet and toast in the 350-degree oven for 10 minutes. Transfer to a cutting board and coarsely chop. Set aside.
In a large bowl, hand mix toasted walnuts, sugars, cinnamon, baking powder and flour.
In a small bowl, whisk eggs. Add maple extract and whisk until well blended. Add to the flour mixture. Stir a few times. Work the batter together with lightly floured hands. The mixture will be sticky, but persevere. Keep squeezing the batter with your hands, until a dough starts to form. Once the dough is firm, form a ball. Divide the ball into 4 equal pieces.
On a lightly floured surface, place one piece of 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 palms with more flour. Repeat with remaining three pieces of dough. Place two logs per baking sheet. Brush loaves all over with 1 lightly beaten egg.
Bake for 40 minutes, rotating pans halfway through, or until the tops of the loaves are shiny and deep golden. Cool on a rack for about 20 minutes before slicing. Place a loaf on a cutting board. Using a large serrated knife, cut 3/4-inch-thick slices, either straight or on the diagonal. Use a sawing motion to prevent crumbling. Each loaf should yield 9 to 11 cookies. If the cookie is crumbling, then let it cool a few more minutes. Don't let it rest too long, however, or it could become too hard to slice.
Place slices on their sides back on to the baking sheets; place in the still warm oven with the temperature off and the door closed for 30 to 60 minutes. 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.
To make the maple icing, mix the confectioners' sugar and maple syrup in a small bowl and whisk briskly until the icing is smooth and opaque and clings to the back of a spoon. Taste. Add more maple syrup and/or confectioners' sugar, if desired.
Dip a teaspoon into the icing and drizzle the spoon back-and-forth over the biscotti. Allow to dry completely before storing. Store biscotti in an airtight container, preferably a tin, which helps keep them crisp. Place parchment paper or waxed paper between layers of cookies to protect the icing. Stored properly, these biscotti will last up to 2 weeks. After that, the icing may begin to appear chalky.