Guaranteed Juicy Burgers

Ingredients
2 pounds ground chuck
1 pound ground sirloin
1/2 cup seasoned dry bread crumbs
3 tablespoons steak sauce of choice
4 egg yolks
1 1/2 teaspoons kosher salt
3/4 teaspoon freshly ground black pepper
4 tablespoons cold sliced butter (1 slice per burger)
10 hamburger buns
toppings of choice

Directions
Carefully mix the meats, bread crumbs, steak sauce, eggs, salt, and pepper with the tines of a fork, but do not mash them. Divide the meat into 10 equal-sized balls. Make an indentation with your finger in the middle of each ball. Place the slice of cold butter in the dent. Lightly form hamburger patties and press lightly into shape [sliced butter should be encased by the meat in the center of each patty].

Cook the hamburgers for 4 minutes on 1 side, then turn and cook 3 minutes on the other side for medium. Remove to a plate and cover with aluminum foil. Allow the hamburgers to rest for 5 minutes [don't skip this step as the burgers will continue to cook while resting]. Meanwhile, grill the buns, cut side down with butter, for 1 minute, until toasted.