If lamb siniyah is a Middle Eastern take on the shepherd’s pie, then this is my North African take, with a butterbean mash standing in for the potatoes. It’s rich, comforting and hearty, needing little more than a green salad or roasted carrots alongside. Make this up to 2 days in advance, to the point where it goes in the oven. If baked straight from the fridge it will need an extra 5–10 minutes. Without the butterbean mash, it can be frozen for 1 month.<