Mix the cream cheese with the creme fraîche. Add mustard, honey and a pinch of salt. It should be very runny honey so that it dissolves well in the cream cheese. Mix the whole cream thoroughly and refrigerate while the dates are being prepared.
Cut the dates lengthways and core them. Put the cream cheese cream in a piping bag with the narrowest possible nozzle. Now use the piping bag to pour the cream into the dates - they can be really full. Chill until ready to serve.