For the Cookies:

Preheat oven to 350 degrees.

Whisk together flour, baking powder and soda, and salt. In a mixing bowl, cream sugar and butter until mixed, one to two minutes. Add eggs and vanilla or liqueur and beat till light and fluffy. Reduce speed to low and add flour mixture. Stir in nuts, if using.  Remove half of dough and add chocolate to the remaining. Mix lightly.

Divide each portion, the chocolate and vanilla in half. On a lightly floured surface roll each portion out into a 6 x 3″ log. Place one chocolate portion onto each vanilla portion. Roll again into about a 10 x 4 1/2″ log. They will spread so leave lots of room. You can vary the measurements, but it alters the baking time so watch closely.

Place each log three inches apart on a baking sheet and bake 20 to 28 minutes until the vanilla portion just begins to show a bit of color. Let cool for 15 minutes and slice carefully into half-inch slices on the diagonal. (Save any crumbs to sprinkle over ice cream.)

Place each cookie with a cut side down on the cookie sheet and bake an additional 14 – 18 minutes, turning halfway through. The outside should be just golden brown when finished.

For the Drizzle (optional)

When the cookies come out of the oven, melt each type of chip with one teaspoon of butter or shortening. (Do this in the microwave in short intervals of about 25 seconds, stirring after each interval, until melted.)

Once the cookies are cool, drizzle the chocolate over the cookies using a spoon, or if you’d like a more professional look, use a pastry bag and small tip. You can sub the pastry bag by using a Ziploc with a corner snipped off. It’s messier, though.

Additional notes:

• Use a very thin sharp knife to cut, with a very specific motion: Drag the tip through till near the end of the slice, then bring the knife down – it seems to make better cuts with fewer crumbs.
• An offset spatula helps to move the hot cut, but not yet twice-baked cookies, a couple at a time to where they need to be on the cookie sheet.

Nutrition for Black and White Biscotti, per cookie:

Cal 86, Cal fr fat 26, 33%, tot fat 3g, sat fat 2 g, chol 14mg; sod 61mg, tot carb 12g; fib .5g; sug 6g; fib 1.5 g