Place the beef tongue in a pot, add ½ gallon [2 liters] of water, and add oregano, a teaspoon of salt, bay leaf, and peppercorns. Cook over medium heat the tongue, until it is tender throughout, which you can test by poking with a fork, and the skin will peel off very easily (40-60 minutes). Discard the bay leaf. Remove the tongue from the water (reserve 1 cup of the liquid it boiled in and set aside for later). Cool to room temperature.
Peel the skin off the tongue. Discard skin. With a sharp knife, cut the tongue into fine slices.
Heat the oil in a skillet over high heat. Add the tongue slices and brown on one, then flip to brown the other side.
Lower heat to medium and add the onion. Cook and stir until the onions become translucent. Stir in the garlic, bell peppers, carrots, olives, and Scotch bonnet pepper. Cook and stir for a minute. Add the tomatoes and tomato sauce. Cover and cook over low heat until the tomatoes are soft.Add the broth that you had set aside and simmer until it is reduced to a thick sauce. Stir in cilantro leaves and season with salt and pepper to taste.
Remove from the heat and serve per the suggestions above.