Combine first 8 ingredients in a large bowl. Combine coffee granules and hot water in a small bowl. Stir in vanilla and next 2 ingredients, and add to flour mixture, stirring until well-blended.
Turn dough out onto a lightly floured surface, and knead lightly 7 or 8 times. Shape dough into a 16-inch-long roll. Place roll on a baking sheet coated with cooking spray, and flatten roll to 1-inch thickness.
Bake at 325° for 30 minutes. Remove the roll from the baking sheet to a wire rack, and let cool for 10 minutes. Cut the roll diagonally into 30 (1/2-inch) slices, and place, cut sides down, on baking sheet. Bake for 10 minutes. Turn cookies over, and bake an additional 10 minutes (cookies will be slightly soft in center but will harden as they cool). Remove cookies from the baking sheet, and let cool completely on wire rack.
This recipe was very easy to make, and I liked that it was fairly quick to put together. I followed the directions exactly, and thought the flavor was delicious. However, I found the cooking time to be way off. I twice baked it (after the initial 30 minute baking time) for 10 minutes on each side, as instructed, and found the biscotti very overdone and almost inedible. Good thing I had a cup of coffee nearby! Will likely make again, but will decrease cooking time, perhaps to 5-6 min on each side.