Recipes: Juiciest burger patties

Preparation:    Preparation time: 25 mins Cooking time: 15 mins Serving: 8 Ingredients: 2 sticks (8 ounces) cold unsalted butter 3 pounds ground beef, preferably sirloin 1 tablespoon kosher salt 8 slices cheese, such as American, cheddar, or Swiss (optional) For serving: split hamburger buns, lettuce, sliced tomato, thinly sliced red onion Instructions:...