• Preheat the oven to 350°F and line two baking sheets with parchment paper.
• In a large mixing bowl, blend the cake mix, eggs, and oil together until the dough is fully incorporated and smooth.
• Portion the dough using an ice cream scoop, spacing each scoop about two inches apart on the prepared baking sheets.
• Bake for 8 to 10 minutes, then let the cookies rest briefly before transferring them to a wire cooling rack. Continue baking remaining dough in batches.

For the Icing

• In a medium saucepan set over medium heat, combine the butter, cocoa powder, and milk. Whisk steadily until the mixture is well blended and smooth.
• Take the pan off the heat and gradually whisk in the powdered sugar until a silky consistency is achieved.
• Set a cookie sheet beneath the cooling rack to catch any excess drizzle. Spoon the icing generously over each cookie. Allow to set before serving.