Whether purchasing it already corned, or making your own, select the brisket that has marbling throughout, and with as little fat on the sides as possible. I have seen store-bought corned beef with such a thick slab of fat on one side that it comprised half of the total weight of the product. Also, at some stores, you can find corned beef made from an eye of round. It can be cooked and easily sliced for sandwiches or meals.
Corned beef, after it has cured, is usually boiled, or par-boiled to remove some of the salt. After that, it can be coated with coarse-grind black pepper, and smoked to make pastrami, or grilled slowly with indirect heat to make it tender. It is very good braised in a slow oven, or slow cooker for several hours. It is just as good braised in a pressure cooker for an hour.
All of these techniques will give you tender meat. If you try to cook it fat, because of the cuts it's made from, it can get tough, sometimes so tough that it's nearly inedible.
For your Reuben, braise in a slow oven, in the pressure cooker, or slow cooker, as described above. The meat will break apart, and shred easily. If you carefully remove the meat slab onto a platter, and let it cool for 15 minutes or so, you can slice it across the grain into either thin, or thicker slices.
Corned beef is great with any kind of potatoes. You can also take some of the broth, dilute it with water to taste, and thicken it with cornstarch to make a very good gravy for rice, or spuds.
Be sure to dice some of that corned beef and cook up with diced potatoes to make you own corned beef hash. I'ts an amazing thing.
Hope this helps.
Seeeeeya; Chief Longwind of the North
