1. Heat butter in a skillet until foam subsides. Add onion; saute until softened but not browned. 2. Add the white wine and reduce by two-thirds. 3. Add the demi-glace or jus de veau. Bring to a boil, then reduce heat and simmer for 10 minutes. 4. If you want bragging rights, strain the sauce through a chinois to produce a very smooth sauce. Otherwise, transfer directly to a bain-marie to hold warm until ready to use. 5. Just before serving, stir in the sugar and mustard. ---------------------------------------------------------------------------
Nutrition
Ingredients
