@crankcasy here in Belgium, ox tongue was a traditional dish on many festive occasions. It is a warm dish, served with Madeira sauce and potato croquettes that are made the day before. Nowadays this dish has almost disappeared but it is still sold in delicatessen butcheries as a ready to heat and eat dish.
Most butcheries also sell the (cold) charcuterie type of ox tongue like you intend to make. I found this picture on the web that really shows the "ox tongue in Madeira sauce" as I remember this delicious dish from my youth;
I had to search a bit further and discovered that still many Flemish foodies make and eat this dish. The name "ox" tongue is a bit stretchable nowadays. In older times, people used those very large ox tongues to feed a bunch of people at a feast table. Nowadays beef and veal tongues are used, all having a different cooking time of course. Let's say that as an average a beef tongue has a cooking time in a traditional pot, of 2,5-4 hours. An average of 3 hours is standard, but the test criterium is always how easily the skin peels off! If the skin doesn't come off easily, the tongue is not done yet, simple as that, but maybe a bit hard to check when it's in a pressure cooker .
When using a very small (!) veal tongue, a cooking time of 45 minutes is possible, again tested by trying to remove the skin.
I have to add that raw tongue is first soaked in salted cold water for 3 hours to remove blood etc.
Secondly, you always bring the tongue to a boil for a few minutes in water only, then remove the dirty cooking water and wash the tongue by rubbing it with your hands under running cold water.
After this procedure, you cook the tongue starting over again with cold water and adding aromats (bouquet marmite).
I also found out that the average cooking time for a larger beef tongue in a pressure cooker is 75-100 minutes.
To make ox tongue in Madeira sauce, you use the bouillon that is a result of cooking the tongue.
Basically it's a velouté sauce on roux base; make a roux, add bouillon, tomato paste, seasoning, mushrooms and at the very end a small glass of Madeira wine (it has to be genuine Madeira, no junk!). Cut the tongue in thin slices and serve covered with the sauce generously over it, or, simply put the slices in the sauce first (which is done often) and serve on large platters.
Edited by ChrisBelgium - 1/24/15 at 5:59am