Ingredients: 2 cups all-purpose flour
1/2 cup unsweetened cocoa powder
1 teaspoon baking soda
1 teaspoon salt
3/4 stick (6 tablespoons) unsalted butter, softened
1 cup granulated sugar
2 large eggs
1 cup walnuts, chopped
3/4 cup semisweet chocolate chips
1 tablespoon powdered sugar
Method :
Preheat oven to 350 degrees. Butter and flour a large baking heet.
In a bowl whisk together flour, cocoa powder, baking soda and salt. In the bowl of a stand mixer fitted with paddle attachment or in a large bowl using an electric mixer, beat together butter and granulated sugar until light and fluffy, about 3 minutes. Add eggs one at a time and beat until well combined. Stir in flour mixture until a stiff dough. Stir in walnuts and chocolate chips.
With floured hands form dough into two slightly flattened logs on the prepared baking sheet. Each log should be about 12 inches long and 2 inches wide. Sprinkle with powdered sugar. Bake 35 minutes or until slightly firm to the touch. Cool on baking sheet 5 minutes, leaving oven on.
On 
a cutting board, cut logs diagonally into 3/4-inch slices to form biscotti. Arrange cut sides down on baking sheet and bake until crisp, about 10 minutes. Cool completely on a wire rack.
Biscotti keep in airtight containers 1 week and frozen, 1 month.