Preheat oven to 350℉. Line two baking sheets with silicone baking mats or parchment paper
Using a wooden spoon or rubber spatula, blend the cake mix (not the small packet), oil, 3 tablespoons of water, and the egg until mixed. Add chocolate chips.
Transfer ¼ of this dough to a small bowl and stir in the contents of the small packet with 1 tablespoon of water.
Spoon the dark dough over the light dough and swirl as you would a cake mix, being careful not to combine them. You want a definition between the colors.
Using a cookie scoop, drop dough onto prepared baking sheets about 2 inches apart.
Bake at 350℉ for 10 to 12 minutes until the edges are light brown.
Remove from oven and allow to cool on cookie sheet for 1 minute before removing cookies to a cooling rack to cool completely.