Preheat the oven to 350° F.
Cut the celery hearts into quarters and blanch for 4 minutes in 1 quart of boiling water.
Drain the hearts and place in a gratin dish just large enough to hold them in a single layer.
Season with white pepper and vegetable seasoning, pour the stock over the celery, cover the pan with foil, and bake for 8 to 10 minutes.
Remove the foil, sprinkle the celery with Parmesan cheese, and place under the broiler for a minute or so, until the cheese is golden brown.
With a slotted spoon, transfer the celery to a heated serving dish. (The stock remaining can be used as a base for soup.)