Chocolate biscotti, one of the best chocolate cookie recipes.

Ingredients

• 6 tablespoons unsalted butter (softened, plus more for the baking sheet)
• 2 cups all-purpose flour (plus more for baking sheet)
• 1/2 cup unsweetened cocoa powder
• 1 teaspoon baking soda
• 1/4 teaspoon salt
• 1 cup sugar
• 2 eggs
• 1 cup pistachio nuts (shelled (or almonds or hazelnuts))
• 1/2 cup chocolate chips ((optional))