This is one of the 5 French “Mother” Sauces
6 tbsps canola oil
1 onion chopped
1 carrot chopped
1 stalk celery chopped
3 tbsps flour
1 generous tsp tomato paste (unflavored)
3 chopped mushrooms
4 cups beef stock plus 1 cup more beef stock
Heat oil in a pan and saute the vegetables until translucent and almost brown.
Add 3 tbsps flour and cook for about 3-4 minutes, whisking constantly.
Stir in 1 generous tsp of tomato paste, 3 finely chopped mushrooms and 4 cups cold beef stock.
Bring to a boil, whisking constantly. Reduce heat to a slow simmer and cook or 35-40 minutes. Skim from time to time.
Add 1 cup more beef stock and cook another 5-10 minutes, skimming.
Remove and strain. Return to saucepan, taste for salt and pepper, and simmer about 5-6 minutes more till slightly thickened and glossy.
TO MAKE DEMI GLACE:
1 cup brown sauce
1 cup beef stock
1 bouquet garni (cheesecloth with 2 bay leaves, fresh thyme and fresh parsley tied up)
Put all in a saucepan and simmer 40-45 minutes until reduced in half. Remove the bouquet garni
Sauce is ready to use. I store in a tightly covered container in my refrigerator for about a week or you can freeze it.