In a medium bowl, cream together butter and sugar for 2-3 minutes until light, fluffy, and pale yellow. Mix in salt, flour, cake mix, sprinkles, and vanilla. Add water one tablespoon at a time, mixing after each, until you reach cookie dough consistency.
Recipe by Willow Bird Baking at http://willowbirdbaking.com/2011/03/20/three-safe-to-eat-cookie-doughs-chocolate-chip-sugar-and-cake-batter/