Preheat your oven to 350°F (175°C) and line your baking sheets with parchment paper.

In a large mixing bowl, cream together the softened unsalted butter, granulated sugar, and brown sugar until light and fluffy, about 3-5 minutes.

Beat in the eggs one at a time, fully incorporating each before adding the next. Then mix in the vanilla extract.

In a separate bowl, sift together all-purpose flour, cocoa powder, baking soda, and salt.

Gradually add the dry ingredients into the wet mixture, stirring gently until just combined.

Fold in the Sixlets candy (or chocolate chips) until evenly distributed.

Using a scoop, place tablespoon-sized balls of dough onto the prepared baking sheets, spacing them about 2 inches apart.

Bake for 10-12 minutes or until the edges are set but the centers are still soft.

Allow the cookies to cool on the baking sheets for about 5 minutes before transferring to a wire rack to cool completely.