I used a 9×13 pan for the crayons cake. Then I cut down about an inch and sliced it in half until that cut. The crayons are ice cream cake cups frosted.
The colors I just mixed until I got the right shade. I used regular store frosting. I should have frosted it first with an icing made of powdered sugar & water.
Once one does this, let it sit for 20 minutes or so so it can hardened then the crumbs won’t get in the frosting.