Which ingredient contributes to the nostalgic flavor of the Dreamsicle cocktail?

The ingredient that contributes to the nostalgic flavor of the Dreamsicle cocktail is orange juice. This flavor profile is reminiscent of the classic ice cream treat known as the creamsicle, which features a combination of orange and creamy vanilla flavors. The sweetness and citrusy tang of orange juice are essential in replicating that bright, refreshing, and summery taste that evokes childhood memories associated with enjoying a Dreamsicle. Orange juice provides not just flavor, but also acidity and balance to the cocktail, enhancing its overall character and authenticity.