Demi-Glace

Preparation

1. In a large saucepan sauté the onions, celery, and carrots in the butter until browned.
2. Add the flour and stir over moderate heat to make a brown roux.
3. Whisk in half the stock and then add the tomato.
4. Enclose the bay, thyme, and parsley in a cheesecloth sachet and ad