2 pounds ground chuck
1 pound ground sirloin
1/2 cup seasoned dry bread crumbs
1/4 cup steak sauce (recommended: Crosse and Blackwell)
3 extra-large eggs
1 1/2 teaspoons kosher salt
3/4 teaspoon freshly ground black pepper
8 to 10 hamburger buns
8 ounces blue cheese, sliced (recommended: Danish Blue)
Arugula and sliced tomatoes, for serving, optional
In a large bowl, carefully mix the meats, bread crumbs, steak sauce, eggs, salt, and pepper with the tines of a fork, but do not mash them. Lightly form into 8 to 10 hamburger patties and press lightly into shape.
Prepare a charcoal or a stove-top grill.
Cook the hamburgers for 4 minutes on 1 side, then turn and cook 3 minutes on the other side for medium-rare. Remove to a plate and cover with aluminum foil. Allow the hamburgers to rest for 5 minutes. Meanwhile, grill the buns, cut side down, for 1 minute, until toasted. Place a hamburger and a slice of blue cheese in each bun, plus arugula and tomato, if desired, and serve hot.
Source: Ina Garten