Makes: about 4 dozen cookies. Prep: 20 minutes. Bake: at 350 degrees for 55 minutes.
Heat oven to 350°F. In a large bowl, whisk flour, cocoa, baking powder, cinnamon and salt. Set aside.
In second large bowl, beat butter and sugar on medium-high until smooth, about 3 minutes. Add eggs; beat until smooth. Gradually beat in flour mixture until just combined. Chop 1 cup of the walnuts; stir in along with chocolate chips.
Shape into 2 logs, 12 inches long. Place on ungreased baking sheet; flatten to 3 inches wide. Bake at 350°F for 35 minutes. Remove logs to wire racks; let cool 15 minutes.
Cut logs into 1/2-inch-thick slices with serrated knife. Place on baking sheets, cut side down. Bake at 350°F for 20 minutes.
Melt white chocolate and shortening in microwave on HIGH for 1 to 2 minutes. Cool slightly. Finely chop remaining 1/4 cup walnuts. Dip end of biscotti into chocolate. Sprinkle with chopped nuts. Let set up on waxed-paper-lined baking sheets at room temperature.