Place tongues in a pot just large to hold them both and cover with water. Cover pot and bring to a boil. Lower heat and simmer 1 1/2 hours. Remove from heat and allow to cool.
Peel tongues and remove fatty parts from lower portion of muscle. Slice tongues into 1/2-inch pieces and set aside.
In a heavy bottom Dutch oven, heat olive oil over medium heat. Add onions, celery and carrots and cook, stirring regularly until lightly browned, about 8 to 10 minutes. Add orange juice, vinegar, chicken stock and tomato sauce and bring to boil. Add tongue pieces and cook uncovered at a very low boil until liquid has reduced by two-thirds, about 30 minutes. Serve with torzelli (separate recipe) and sprinkle with grated orange zest.
BASIC TOMATO SAUCE
1 Spanish onion, cut into 1/4-inch dice
4 cloves garlic, thinly sliced
3 ounces virgin olive oil
4 tablespoons fresh thyme (or 2 tablespoons dried)
1/2 medium carrot, finely shredded
2 28-ounce cans of tomatoes, crushed and mixed well with their juices
Salt, to taste
