Ingredients: 2 cups balsamic vinegar 3 or 4 ounces cold, high quality butter, cut into chunks For extra special occasions use truffle butter Directions: In a small saucepan, bring the balsamic vinegar to a simmer and reduce by 2/3. One chunk at a time, swirl in the butter and combine until it's completely melted, and the sauce has a smooth, velvety consistency. Serve immediately over filet mignon or other fine steak.