What ingredient is famously used in the Carl's Jr. Western Bacon Cheeseburger?

The ingredient that is famously used in the Carl's Jr. Western Bacon Cheeseburger is onion rings. This burger is well-known for its distinctive combination of flavors, which includes a charbroiled beef patty topped with crispy onion rings. The onion rings add a delightful crunch and a slightly sweet flavor that complements the savory notes of the burger.

Additionally, while bacon, BBQ sauce, and cheddar cheese are elements found in various burgers, the inclusion of onion rings is specifically what differentiates the Western Bacon Cheeseburger and serves as a signature feature. This highlights the unique take Carl's Jr. has on traditional burger offerings, making it memorable for customers who enjoy that particular combination.