Clean, wash and drain the rocket very well. If necessary put something aside for garnishing. Mix crème fraîche and wasabi. Remove the crusts from the bread and spread with the wasabi cream.
Layer 6 slices of rocket salad and roast beef on top. Place the rest of the bread on top and press down lightly. Quarter the slices and put them together with skewers as desired. Garnish with rocket salad.