★★★★☆ 8.3/10 (4 check-ins)
This limited-edition special brings West Coast smash mechanics to the UK chain. Shifting away from their usual thick-puck style, it features double smashed beef patties seared directly with American mustard on the grill for an intense, savory crust. It's stacked with double American cheese, bacon, grilled onions, lettuce, tomato, and pickles. The wildcard is a decadent brown butter burger sauce that grounds the fresh, bright veggies with a rich, nuttily savory finish.