Heat a grill pan, brush the rump steaks with olive oil, season and cook to your preference (2 mins a side for rare, 3 for medium-rare and 4 for well-done). Leave to rest for 10 minutes.
To make the chermoula blend in a food processor all ingredients apart from the California Walnuts.
Toast the California Walnuts then roughly chop. Mix together in a bowl along with the chermoula
Slice the rolls, drizzle with olive oil then toast in a grill pan
Slice the steak then arrange on the rolls under a few leaves of rocket. Top with the California Walnut chermoula