Mix together all the ingredients in a mixing bowl.
Put the butter onto a piece of plastic wrap and shape into a log. Roll it up tightly and twist the ends to close. Put the butter into the refrigerator until firm, about 2 hours.
To use the Café de Paris butter, slice off pieces and let them come to room temperature (this is optional, but helps the butter melt faster). Put the butter onto hot, cooked steaks.
