This is a very rich and filling dish. When friends come round for dinner, I simply serve it with a bowl of couscous, followed by fruit. Orange slices dusted with ground ginger and ground cardamom are especially good.
Season the beef with salt and pepper. Heat the oil in a large frying pan over a high heat. Reduce the heat to medium, add the beef and fry for 3–5 minutes until browned on all sides, working in batches to avoid overcrowding the pan and adding extra oil, if necessary. Use a slotted spoon to transfer the beef to the slow cooker, then add the aubergine, dates and preserved lemons.