Preheat oven to 350°F. Mix flour, brownie mix, cocoa powder and cinnamon in large bowl with electric mixer on low speed until well blended. (If using a stand mixer, use the wire whisk attachment.) Mix eggs, coffee, oil and vanilla in medium bowl until well blended. Gradually add to flour mixture, beating on low speed until well mixed. Stir in chocolate chips.
Divide dough in half. Shape each half into a 12-inch long log. Transfer logs to parchment paper-lined baking sheet. Flatten logs to 1-inch thickness.
Bake 30 to 35 minutes or until slightly risen and firm to touch. Cool logs on wire rack 10 minutes or until cool enough to handle. Transfer to cutting board. Using a sharp serrated knife, cut logs diagonally into 3/4-inch thick slices. Place slices, cut sides down, in single layer on parchment paper-lined baking sheets.
Bake 10 to 15 minutes or until crisp, turning biscotti over halfway through cook time. Remove biscotti to wire racks; cool completely.
Test Kitchen Tips:
•For a softer biscotti, skip step 4—no need to bake a second time.
•For a flavorful twist, omit Cinnamon and use 1 tablespoon McCormick® Ground Ginger or 2 tablespoons Gourmet Garden® Ginger Stir-In Paste instead!
•Try dipping cooled biscotti in melted chocolate. Sprinkle with chopped nuts, colored sprinkles, dried fruit, or coconut!