Which ingredient is NOT found in the Classic Cheeseburger?

The Classic Cheeseburger typically includes staple ingredients that are classic to its traditional recipe, such as tomato and red onion, which contribute to the burger's freshness and flavor profile. Garlic aioli, while not standard in every cheeseburger recipe, can be a common addition to enhance the taste. In contrast, spicy candied bacon, while it may be a delicious ingredient featured in various burger creations, is not part of the Classic Cheeseburger's essential components. Hence, identifying spicy candied bacon as the ingredient not found in the Classic Cheeseburger indicates an understanding of the traditional recipe versus variations that incorporate additional toppings.