¾ cup refrigerated or frozen egg product, thawed, or 3 eggs, lightly beaten
1 teaspoon vanilla
2½ cups all-purpose flour
2 tablespoons unsweetened cocoa powder
2 tablespoons instant espresso coffee powder
2 tablespoons all-purpose flour
½ cup semisweet chocolate pieces and/or white baking pieces
Preheat oven to 375°F. In a large bowl, combine butter and cream cheese; beat with an electric mixer on medium to high speed for 30 seconds. Add sugar and baking powder; beat until combined, scraping side of bowl occasionally. Add eggs and vanilla; beat until combined. Beat in as much of the 2½ cups flour as you can with the mixer. Using a wooden spoon, stir in any of the remaining flour.
Divide dough in half; transfer half of the dough to a medium bowl. In a small bowl, combine cocoa powder and espresso powder. Add to half of the dough; knead with hands until combined. Add the 2 tablespoons flour to the remaining half of the dough; knead with hands until combined.
Divide each half of the dough into two equal portions. Shape each dough portion into a rope about 12 inches long. Twist one chocolate rope and one plain rope together. Gently roll twisted ropes together to form a 14-inch-long rope. Place on a large cookie sheet lined with parchment paper. Pat down to make a log about 2 inches wide. Repeat with the remaining ropes to make two logs total, placing logs about 4 inches apart on the cookie sheet.
Bake about 18 minutes or until lightly browned. Cool on cookie sheet for 1 hour.
Preheat oven to 325°F. Transfer baked logs to a cutting board. Bias-slice logs into ½-inch-thick slices. Place slices on the same cookie sheet. Bake in the 325°F oven for 8 minutes. Turn slices over; bake for 8 to 10 minutes more or until dry, crisp, and lightly browned. Transfer cookies to a wire rack; cool.
In a small saucepan, heat chocolate pieces over low heat until melted. (If using both semisweet chocolate and white baking pieces, melt in separate saucepans.) Cool slightly. Drizzle over cooled biscotti. Let stand until set.
Tip: Because sugar gives the biscotti its classic crispness, we do not recommend using a sugar substitute for this recipe.
Storage: Layer between waxed paper in an airtight container; cover. Store at room temperature for up to 2 days or freeze for up to 3 months.