1. Soak the brains in water to cover with two teaspoons salt for fifteen minutes. Remove the covering membrane and veins.
2. Drop the brains into boiling bouillon and add the carrot, celery, onion, bay leaf and thyme. Reduce heat and simmer, covered, for thirty minutes.
3. Remove the brains, slice and place on a hot serving dish. Brown the butter, add the vinegar and capers and pour over the brains.