Mix cake mix, oil, and eggs together (do not follow the directions on the back of the cake mix- disregard them completely).
Drop spoonfuls of dough onto baking sheet. Bake for 6-9 minutes (don't cook any longer than that! You don't want them to be overdone). Let cookies cool completely.
Frosting
Mix together all the ingredients (add more or less powdered sugar until you get the consistency you like). Spread on top of each cooled cookie.
Chocolate Topping
Melt chocolate chips and butter together in a double boiler OR in a microwave (I usually microwave for 30-second intervals, then stir and repeat until the chips are fully melted).
Spread melted chocolate on each cookie- I have found that it works best to use the back of a spoon to spread the chocolate around.
Let chocolate set up and then serve.
Notes
These little cookies are super rich! I think that if you didn't want them to be so rich, use a milk chocolate cake mix and milk chocolate chips.