01 -
Pop some parchment paper into your 9-inch pan. It'll make cleanup and lifting a breeze!
02 -
Toss the white chocolate chips, dry cake mix, and marshmallow fluff into a big mixing bowl. Leave it set aside.
03 -
In a saucepan, heat up butter, sugar, cream, and a little salt over medium. Keep stirring 'til it's bubbling nicely.
04 -
Let that bubble go wild for 4 minutes. Stay there and keep stirring the whole time—no stopping!
05 -
Take the hot mixture and pour it over the stuff in your bowl. On low speed, mix it until the chocolate's melted. Stir most of your sprinkles in at the end.
06 -
Pour it all into your prepared pan. Quickly scatter the rest of the rainbow sprinkles evenly over the top.
07 -
The toughest part—let it sit untouched for about 4 hours 'til it firms up just right.