Oven preheating will happen in Instruction #4, so cookies can chill for 10-15 minutes.
In a large mixing bowl, combine the cake mix, oil, and eggs together and mix together until just incorporated.
Add the chocolate chips & candies and mix well.
Preheat your oven to 350 degrees F and line a cookie sheet with parchment paper or a silicone baking sheet. Alternatively, you could spray it with nonstick cooking spray.
Use a medium cookie scoop to scoop even-sized cookie dough balls and place in fridge for 10-15 minutes while your oven preheats.
When you’re ready to bake, place cookies 2 inches apart.
Bake cookies for 8-10 minutes.
Transfer to a baking rack and let cookies cool.
Once cookies are cooled, frost the cookies with an offset spatula or transfer frosting to a pastry/piping bag and pipe onto cookies.
Sprinkle rainbow chocolate chips or mini m&m’s on top of cookies and let the frosting firm up.