This is a supper simple recipe from Serious Eats for beef tongue tacos made with a sous vide setup (though they do include alternate stove top braising instructions). All you are doing is putting your big ole cow tongue in a bag with tomatoes, onion, cilantro, and duck fat so that after 24-48 hours in the water bath (at 170 degrees F) you also have the basis for a salsa.
If you've never dealt with beef tongue before, you do have to handle the fact that it is indeed an animal's tongue and there is really no mistaking that. What that means, besides however "gross" you might think it looks, is that you have to peel the outer layer off before dicing up the rest of the muscle. I didn't have any problem with this... and I'm not an offal person in general... but obviously your mileage may vary. Personally I think if you are eating meat you should be comfortable with the fact that said meat came from an animal with a face (and a tongue)... but I suppose that doesn't mean you should have to want to eat it, however I think you'd be missing out since it is just like any other muscle in most respects.
Circling back around to the recipe... I had two relatively minor problems with it. The first is that it calls for 1.5 lbs of cow (or veal) tongue which, in the case of cows, is physically impossible. Cows are big animals, so you are looking at something more on the order of 3 lbs and butchers don't generally sell them in pieces (at least in my experience). So you either need access to veal tongue, to double the recipe, or a friend who also wants half a cow tongue... which worked for me, believe it or not, but seems like it would be somewhat uncommon in general. The second issue is that, once your beef tongue is done cooking, you divide the resulting liquid into two parts... one half to make the salsa and the other to reduce on the stove top with the tongue. The instructions say "Combine tongue and remaining liquid in heavy-bottomed 10 or 12-inch skillet. Bring to a simmer over high heat, reduce to medium and cook, stirring frequently, until liquid is reduced and tongue has started to crisp, about 8 minutes." Emphasis mine. How exactly does that work? Can you crisp something in liquid? Well if it's fat, yes, and so I suppose it means for you to cook off the water and then fry the tongue up a bit... but all my liquid cooked off with no "crisping" so I ended up deglazing and going with it as is. I also found I preferred to just mix my beef tongue in with the chipotle salsa instead of keeping them separate, so I'm not sure there is really anything to be gained from that step.
Otherwise it's a solid recipe. Super simple and a great way to use a sous vide setup.