Yield: 40 biscotti
1.Preheat oven to 350F. Line a baking sheet with parchment or non-stick liner. Place peanuts in the bowl of a food processor and pulse until peanuts are medium fine. In a medium bowl combine and whisk together the crushed peanuts, flour, sugar, salt, baking powder and baking soda. (If using chocolate chips add at this time.) Set aside.
2. In the bowl of a mixer with the paddle attachment, combine eggs, egg whites, peanut butter and vanilla and mix until smooth. Add the flour-peanut mixture and beat until ingredients are incorporated. (The dough will be slightly wet and there will be some peanut and flour bits in the bottom of the bowl.)
3. Pour mixture onto a lightly floured board and with lightly floured hands to keep the dough from sticking, knead the peanut and flour bits until they are completely incorporated into the dough.
4. Divide the dough in half. Shape each half into logs 11-inches long by 3-inches wide. Place onto prepared baking sheets allowing approximately 4-inches between the logs. Bake for 20 minutes, rotate pan and bake an additional 15 to 20 minutes or until logs are firm to the touch. Transfer to a wire rack and cool completely before slicing.
5. Reduce oven to 325°F. Place logs on a cutting board. Using serrated knife slice on a diagonal into 1/2 inch pieces. Lay slices flat on a baking rack placed on a baking sheet. Place in oven. Bake for 15 minutes, rotate pan and bake for an additional 15 minutes or until dry and crisp. Remove from the oven and cool before dipping.
6. Dipping Chocolate: In the top of a double boiler combine chopped semisweet chocolate and vegetable shortening. Simmer and stir until chocolate melts and mixture is smooth. Line a baking sheet with parchment or waxed paper. Dip the round edge of biscotti into chocolate to coat, letting any excess drip back into pan. Stand slices up on baking sheet until chocolate is firm. Store biscotti in an airtight container between sheets of waxed paper.