In a large bowl, cream together the butter, white sugar, and brown sugar until light and fluffy. Beat in the egg and vanilla extract. Mix in the cocoa powder. Combine the flour, baking soda, and salt; stir into the batter until just blended.
Drop rounded tablespoonfuls of dough onto ungreased baking sheets. Sprinkle with coarse sugar. Bake for 10 minutes in the preheated oven, or until set. Allow cookies to cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Interesting Facts
Chocolate-crackle cookies are a type of cookie that originated in the United States.
The cookie is made with cocoa powder, giving it a deep chocolate flavor.
The cookie is also coated in coarse sugar, giving it a crunchy texture.