- cooking spray
- 1 (18.25 ounce) package yellow cake mix
- 1/2 cup butter, softened
- 1 egg
- 2/3 cup multi-colored sprinkles, divided
- 1 cup white chocolate chips
- 1/2 cup sweetened condensed milk
- Preheat oven to 350 degrees F (175 degrees C). Line a 9×9-inch pan with aluminum foil and spray liberally with cooking spray.
- Mix yellow cake mix, butter, and egg together in an electric stand mixer fitted with the paddle attachment until a thick dough forms, add 1/3 cup multi-colored sprinkles and mix to incorporate.
- Press 2/3 of the dough into bottom of prepared pan; sprinkle white chocolate chips and remaining 1/3 cup multi-colored sprinkles over top, followed by sweetened condensed milk. Roll remaining 1/3 of the dough into balls and arrange evenly over top of contents in baking dish, pressing down to flatten.
- Bake in preheated oven until it just begins to brown, about 30 minutes. Cool completely on wire rack before cutting, about 1 hour.