The beef cut is actually a top blade steak derived from the tender top blade roast. The roast is separated into two pieces by cutting horizontally through the center to remove the heavy connective tissue.
The blade chuck consists of three distinct types of meat, two of which are steaks normally sold at a premium? one of which is the Flatiron steak and is considered by many as the finest cut of beef available.
Identify the blade chuck by its two major characteristics. First, the blade-shaped bone at the top of the roast, which should not have any protuberances on it (otherwise, it is a center-cut or seven-bone chuck). Second, the words, "blade chuck" on the supermarket packaging. (This latter is less reliable.)
When you get the roast home, divide it into its three pieces, removing the bones in the process.
First, remove the meat above the blade (cut 1). This is the Flatiron steak. It is a little tough. Some prefer to use it for stir-fry or stroganoff, although many people simple halve it and cook it up as a couple of steaks.
Second, the steer has been kind enough to provide a line of fat as a guide to removing the chuck eye (2) from the remaining meat (3). Just cut along the white line to separate the steak. You may then cut the steak away from the chine bone that lies along the bottom or you can barbecue the whole thing up, bone-on. Either way, you will be eating a premium steak at hamburger prices.