Complex sentence: As Luca won the mystery box, he received the usual advantages: immunity from competition and choice of an American classic dessert his fellow competitors would have to make, among twenty-four cookies, twelve cupcakes, or a classic three-layer cake.
Split into simpler sentences: As Luca won the mystery box, he received the usual advantages: immunity from competition and choice of the item which his fellow competitors would have to make. In this case, the judges presented to Luca three American classic desserts: twenty-four cookies, twelve cupcakes, and a classic three-layer cake.