There are secret weapons in the quest for umami, the so-called fifth flavor, which is a combination of savoriness and deep satisfaction. The wrongly maligned MSG is one of them. There's also tomato paste, anchovies, and the Japanese seaweed and fish broth called dashi. Chief among the ingredients, however, is mushrooms. Vegetarians for years have relied on fungi for meaty satisfaction. Jr's, the humble Miami Springs restaurant that in 2015 finally got some long-overdue recognition when it won the South Beach Wine & Food Festival's Burger Bash, deploys a panoply of everything from button mushrooms to shiitake, porcini, and oysters on its wild mushroom burger ($8.85/$9.99) to create an umami bomb tucked in a bun. Take in each bite with a pull of Swiss cheese and a few strands of sautéed onions, and you have all the makings of midday ecstasy.