heard cows tongue is good but ive never tried it, i buy it for dog food, think i heard somewhere that you lightly boil it to get the rough skin off then peel the skin off it and dice it, havent a clue where you go from there though as my hubby once found one in the fridge growing up, his father had bought it for the dinner, all the kids went on hunger strike for the day, his dad couldnt understand why but then he did try to serve it to them in one whole piece, still looked like a cow tongue when he served it
this recipe looks good however; http://allrecipes.com//Recipe/lengua-beef-tongue/