Preheat oven to 350 degrees F (175 degrees C). Grease cookie sheets.
In a medium bowl, cream together the butter and sugar until light and fluffy. Beat in the egg and vanilla.
In a separate bowl, combine the flour, baking powder, and salt. Gradually stir the dry ingredients into the wet mixture until well blended.
Divide the dough in half and place in two separate bowls. Stir the chocolate chips into one half of the dough, and stir the cocoa powder into the other half.
Roll each half of dough into a 10 inch log. Place the two logs side by side and twist them together. Using a sharp knife, cut the log into 1/2 inch thick slices.
Place the slices on the prepared cookie sheets. Bake for 12 to 15 minutes in the preheated oven, until golden brown.
Interesting Facts
Checkerboard cookies are a classic cookie flavor combination.
The checkerboard pattern is created by twisting together two different colored doughs, resulting in a unique and striking cookie.
These cookies are great to make with kids, as the twisting together of the dough is a fun activity.