The first time i made these for my family, i didnt mention the fact that they were half mushroom, half beef (otherwise known as the blend i feel like it needs a soundtrack to go with this dramatic name); i just said they were burgers. No questions were asked, and the burgers were completely devoured. According to the mushroom council, many chefs are finding that you can blend chopped mushrooms with ground meat to create better tasting, more nutritious burgers good for you, but also good for the environment, as even non-vegetarians know that reducing overall consumption of meat is a great thing for the earth. Mushrooms, like beef, are a great source of umami, which is also known as the fifth taste think meaty, think deep, think a pleasant savory taste which is how it translates from japanese. Mushrooms are extremely low in calories, and have no fat, so by blending them with flavorful, rich ground beef, you get the best of both worlds. You can use this technique with all kinds of meat, from beef to lamb to buffalo to sausage to turkey. You can also have a very good time exploring the wide world of mushrooms. In this recipe i used a mix of cremini and button mushroom, inexpensive and very readily available, but you should feel very free to change up flavors with other varieties like criminis, portabellas, shiitake, maitake (also known as hen of the woods), oyster, trumpet and more. Richly caramelized onions provide another wonderful depth of flavor to this burger. The longer you can cook the onions, the better, but keep the heat low and stir frequently so that they dont burn.