How do you get a burger made from mild, low-fat turkey to have some of the meaty richness of beef? Add some rich, meaty flavors! Here's the kitchen science: Beef and other red meats contain compounds called glutamates. So do soy sauce and Marmite, which is a powerfully strong yeast extract found in a lot of supermarkets (the Aussies love a version called Vegemite). We add a bit of both to our turkey mixture, lending this burger the umami flavors of real red meat.As for juiciness, another challenge with turkey, that comes from the addition of mildly flavored eggplant. We simply roast the eggplant with olive oil, then puree it, then blend it with the ground meat.