Place the beef tongue in your instant pot along with the onion, garlic, and herbs. Cover with water and cook for 30 minutes. If using a regular pot, cook over medium-high heat until it comes to a boil. Reduce the heat and gently simmer. Cook until it is tender, about 2 hours. Make sure that you cook it until it is tender, but still firm enough to cut into slices.
Once the beef tongue is cooked, wait until it has cooled and then remove the outer skin. Cut into ⅓-inch slices and set aside.
While the beef tongue is cooking, heat 2 tablespoons of oil in a large skillet over medium heat. Fry the bread slices until they are a light golden brown, turning once. Set aside.
In the same skillet, fry the almonds, onion, and garlic clove for about 8 minutes.
Add the tomatoes and keep cooking until the tomatoes have released their juices.
Place this tomato-almond mixture into your blender and add the clove, peppercorns, cinnamon, and sherry. Process until you have a smooth sauce.
Using the same skillet as before, heat the rest of the oil at medium heat and then pour the tomato–almond sauce in. Add 1 cup of the beef tongue’s broth and gently simmer for about 15 minutes. Season with salt.
Add the beef tongue slices and keep cooking for 8 more minutes, until the sauce has reduced.