Place the tongues in a pot just large enough to hold them both, and cover with water. Cover the pot and bring to a boil. Lower the heat and simmer 1 1/2 hours. Remove from heat and allow to cool.
Peel the tongues and remove the fatty parts from the lower portion of muscle. Slice the tongues into 1/2-inch pieces and set aside.
In a heavy-bottomed Dutch oven, heat the olive oil over medium heat. Add the onions, carrots and celery and cook, stirring regularly until lightly browned, about 8 to 10 minutes. Add the orange juice, vinegar, chicken stock and tomato sauce and bring to a boil. Add the tongue pieces and cook, uncovered, at a very low boil, until the liquid has reduced by 2/3, about 30 minutes. Sprinkle with parsley and the grated orange zest.
In a 3-quart saucepan, heat the olive oil over medium heat. Add the onion and garlic and cook until soft and light golden brown, about 8 to 10 minutes. Add the thyme and carrot and cook 5 minutes more, until the carrot is quite soft. Add the tomatoes and juice and bring to a boil, stirring often. Lower the heat and simmer for 30 minutes until as thick as hot cereal. Season with salt and serve. This sauce holds 1 week in the refrigerator or up to 6 months in the freezer.
Recipe copyright 2000, Mario Batali. All Rights Reserved.