Football is back, and that means tailgate parties are back, too! Here's a tasty recipe for you to use before you watch the game. Searing these burgers over a high heat gives them a deliciously charred crust. Top them with a flavorful mixture of sautéed mushrooms and onions. I like my burgers topped with a thick slice of tomato. Recipe adapted from Best Darn Food Ever. Technique adapted from Cooks Illustrated.