Boil a calf's tongue in salted water until tender; skin and slice thin. Then heat 2 tablespoonfuls of butter; add 1 chopped onion; stir in 1 tablespoonful of flour until brown; add 2 cups of the water in which the tongue was cooked, ¼ cup of seeded raisins, a few cloves, 1 bay-leaf, ¼ cup of vinegar, and ½ teaspoonful of paprica. Let all boil well; then add the sliced tongue. Let simmer ten minutes. Serve hot or cold.