In a small bowl sift together the flour and cornstarch.

In a large bowl on medium speed cream butter and sugar until combined, then add the egg and vanilla and beat to combine, then beat in a third of the sifted flour mixture, add the remain flour but combine with a wooden spoon or spatula until almost combined.

Move the dough to a lightly floured flat surface and gently knead until smooth. Wrap in plastic and refrigerate 1 hour.

In a small bowl sift together the flour, cornstarch and cocoa.

In a large bowl on medium speed cream butter and sugar until combined, then add the egg and vanilla and beat to combine, then beat in a third of the sifted flour mixture, add the remain flour but combine with a wooden spoon or spatula until almost combined.

Move the dough to a lightly floured flat surface and gently knead until smooth. Wrap in plastic and refrigerate 1 hour.

Remove the dough from the fridge. Taking small pieces of dough** (either vanilla or chocolate) make small balls (between a marble and a golf ball) then roll into 2 1/4 inch chunky ropes, wrap a chocolate rope around the vanilla rope (or vice versa), gently press down so that the dough sticks.

Place on parchment paper lined cookie sheets, and refrigerate for 30 minutes. Pre-heat oven to 375 F (190 C).

Bake cookies pre-heated oven for approximately 15 minutes or until lightly golden. Let cool completely before serving.

** I rolled and made the cookies with 1/3 of the dough at a time.

Conserve in a air tight container for up to 2 weeks or freeze.