BURGER KING® Restaurants Tailor Japanese Flavored Bun Phenomenon to U.S. Tastes with A.1 Sauce MIAMI, 2015-9-30 — /EPR Retail News/ — BURGER KING® restaurants are launching the A.1. Halloween WHOPPER® sandwich this season, a burger unlike any other in America, with a black bun that has A.1. flavor baked in. While the pitch-black bun gives the Halloween WHOPPER®…