Place tongue in a large pot with onions, carrots, celery and parsley. Add water to cover. Add peppercorns and salt.
3
Simmer gently until tender, for 3 to 5 hours. Drain. Strain and reserve liquid.
4
Make Sauce
5
Heat oil in a saucepan, add flour and stir until blended. Gradually stir in 2 cups reserved liquid, add raisins, lemon slices, and vinegar. simmer until raisins plump and soften, about 20 minutes.
Remove skin from tongue and trim connective tissue on the bottom. Slice thinly, and arrange around a plate. Pour sauce over sliced tongue and serve hot.
