To enhance the flavor of key lime pies, which ingredient is commonly used?

The ingredient that is commonly used to enhance the flavor of key lime pies is lime candy. This choice is particularly effective because it intensifies the citrus notes that are characteristic of key lime pies. Lime candy introduces an additional layer of lime flavor, complementing the tartness of the key lime juice used in the pie. Its sweetness also helps balance the acidity of the limes, resulting in a well-rounded flavor profile.

In contrast, mango puree, chocolate shavings, and cinnamon do not align with the traditional flavor profile of a key lime pie and would not enhance its citrus flavor. Mango puree introduces a tropical fruit sweetness that can overshadow the key lime flavor. Chocolate shavings can create a conflicting taste since chocolate is not traditionally paired with key lime, while cinnamon would bring a spiced element that diverges from the classic refreshing taste associated with key lime pies.