Billy’s Mushroom Swiss Burger is a rich, savory classic done the Burger Billy’s way. We start with our perfectly seasoned 4oz smash patty, grilled to juicy perfection, then top it with tender sautéed mushrooms and two melty slices of Swiss cheese. Crisp lettuce and fresh tomato add the perfect balance, while a bold drizzle of A1 Steak Sauce brings it all together with a tangy, steakhouse kick. Served on a soft, buttery brioche bun, this burger is stacked, satisfying, and built to impress.