Impossible Whoppers are a huge hit at Burger King, fueling its best quarter in four years

Restaurant Brands (QSR) reported solid earnings for the third quarter Monday morning, led by a more than 10% increase in sales at Burger King and nearly 15% surge at Popeyes.The company said sales at Burger King restaurants open at least a year rose 5% in the quarter. That was the strongest growth since 2015. Restaurant Brands attributed the success of the plant-based Impossible Whopper, which has been rolled out to all Burger King locations in the United States, for the strong sales.Popeyes did even better, with same-store sales in the United States soaring more than 10%. Restaurant Brands said that was the best quarter for the chain in nearly two decades.Restaurant Brands and Popeyes have caught lightning in a bottle with the spicy chicken sandwich, a menu item that attracted so much of a cult following that the chain ran out of supply. The success of the sandwich even sparked a Twitter feud between Popeyes and competitor Chick-fil-A.Popeyes announced Monday that the sandwich is coming back on November 3 — as a permanent menu item.It seems safe to say that the runaway success of the spicy chicken sandwich has more than justified Restaurant Brands’ purchase of Popeyes in 2017 for $1.8 billion.Restaurant Brands shares are up more than 30% this year, compared to a nearly 10% rise for top rival McDonald’s (MCD) and about a 20% pop for KFC owner Yum! Brands (YUM). McDonald’s recently reported a slowdown in US sales growth.But there was one bit of bad news for Restaurant Brands. The other chain it owns, doughnut and coffee seller Tim Hortons, is struggling. Sales at Tim Hortons, which competes with Starbucks (SBUX) and Dunkin’ (DNKN), fell in the quarter. The company launched its own plant-based menu item, a breakfast sandwich with sausages from Impossible rival Beyond Meat, earlier this year. Beyond Meat (BYND)will report its earnings after the closing bell Monday.