Which ingredient should be prepared last to maintain freshness?

Lettuce should be prepared last to maintain its freshness because it is a delicate ingredient that can quickly wilt and lose its crisp texture if exposed to moisture or time. Preparing lettuce at the last moment ensures that it retains its crunch and vibrant color, contributing to an appealing and enjoyable texture in a burger or sandwich.

Bacon, while it does need to be cooked to the appropriate temperature, is generally more resilient to time and does not suffer from quality degradation as quickly as fresh vegetables. Tomatoes, though also perishable, can be sliced in advance and will maintain their taste and texture for a short time. Onions, particularly when raw, can also remain stable without significant loss of quality over a brief period.

By prioritizing when each ingredient is prepared, it is crucial to handle more perishable items like lettuce last to provide the best possible eating experience for customers.