Lyonnaise Sauce

Ingredients

• 3 medium onions, minced
• 2 decilitres white wine
• 2 decilitres vinegar
• 3/4 litre demi-glace (rich brown sauce)
• butter

Instructions

1. Melt butter in a pan and cook the minced onions gently over very low heat, ensuring they are cooked almost completely through, until they turn blond (light golden). Deglaze the pan with the white wine and an equal amount of vinegar. Reduce this mixture by two-thirds. Add three-quarters of a litre of demi-glace (rich brown sauce). Let the sauce simmer very gently for 5 to 6 minutes. Pass through a fine strainer (étamine).
2. Note: Depending on the preparation this sauce is destined for, the onions may be left in or strained out.