2 cups balsamic vinegar
3 or 4 ounces cold, high quality butter, cut into chunks
For extra special occasions use truffle butter
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.
immediately over filet mignon or other fine steak.