With a mixer on high speed, beat butter and granulates sugar until fluffy. Add egg whites and beat until well-blended. Stir in flour, cocoa, and baking powder; mix until well blended.

On a buttered 12 x 15" baking sheet, shape dough down the length of the pan into a flat log 2 1/2" wide and 5/8" thick.

Bake in a 350 deg F oven until crusty and firm to touch, about 20 min. Let cool about 5 min.

On pan, cut log diagonally into 1/2" thick slices. Lay slices cut side down (they can touch). Return to oven and bake until cookies feel firm and dry, 15 - 20 min. Transfer to racks; let cool.

Smoothly mix powdered sugar and enough milk to make pourable icing. Using a spoon, drizzle icing decoratively over biscotti. Let stand until icing is dry, about 15 min. Serve, or store airtight up to 1 week.

Makes about 20

Fat 2.6g

Carb 17.5g

Fib 0.5g

Pro 2.3g

Sod 71mg

Cff 22.9%