Remove tongue from the plastic packaging and rinse well.
In a large pot, combine tongue with 1/2 onion (cut into two pieces), 2 garlic cloves, 1 teaspoon salt,1 tsp. whole black peppercorns and bay leaf. Bring to a full boil, cover and reduce heat, continuing to boil for approximately 1 1/2 hours (depending on the size of the tongue) or until the juices run clear when pierced with a fork.
When fully cooked, remove tongue from pot and set aside to cool. Reserve one cup of the cooking liquid. Using a small knife, carefully remove the thick outer layer from the meaty flesh. Remove any unappetizing fatty parts towards the back of the tongue. Once cleaned, cut the tongue into 1/2 inch slices and set aside.
In a large pan over medium heat, add 2 Tbsp. vegetable oil, sliced onions, whole jalapeno, 1/4 teaspoon salt, 1/2 teaspoon fresh ground black pepper and cook until tender and translucent, approximately 10 minutes.
While onions are cooking, toast two slices of white bread and set aside.
In a blender, combine Roma tomatoes, toasted bread and blend until smooth.
Pour tomato mixture into the pan with the cooked onions. Nestle the sliced beef tongue into the sauce. If the sauce seems too thick, add 1/4 cup to 1/2 cup reserved cooking liquid. Add 1/2 cup chopped olives, 1 tablespoon vinegar, 1 tablespoon sugar and stir well to combine.
Simmer approximately 20 minutes or until sauce thickens slightly, taste and correct seasonings adding additional salt if needed.
