In a large bowl cream butter for 2 minutes until smooth with an electric mixer.

Mix in sugar and beat for an additional 2 minutes.

Add in egg and vanilla and mix until well combined.

Sift in flour, salt, and baking soda and mix until just combined.

Remove 2 cups of the dough and set aside.

Add in cooled coffee and cocoa powder to remaing dough.

Mix in melted chocolate until well combined.

Divide each dough into three equal pieces, so as to have 3 chocolate and 3 vanilla.

Shape each piece into a 5×5 square on wax or parchment paper, top with another piece of wax or parchment and refrigerate for 30 minutes.

Roll each square into a 7×7 square and refrigerate for 15 minutes.

Take one vanilla square and one chocolate square and remove one piece of waxed paper from each.

Align the two layers together evenly, one on top of the other, and gently press together to seal both layers together.

Take off top layer of wax paper and slowly start to curl edge of the dough up and over using the bottom waxed paper for help, not rolling it into the cookies.

Roll the dough into a tight spiral roll, pinwheel, avoiding spaces in-between.

Once formed, gently but firmly roll back and forth to compact the roll and make it about 9 inches long, 1.5 inches thick.

Place on a piece of plastic wrap, twisting ends to seal it closed.

Repeat with remaining layers.

Refrigerate for 3 hours before using or freeze for two months.

To bake, preheat oven to 350 F. Line baking sheets with parchment paper and slice cookie log into ¼ inch thick cookie slices.

Bake for 14 minutes and transfer warm cookies to baking rack.

Store for up to two weeks.