Pre-heat the oven to 180°C. Rub the rump with the cumin and season with salt and pepper. In a pan, seal off the rump on all sides, then transfer to an oven dish and bake for 15-20 minutes, until pink/medium and allow to rest for 10 minutes.
In the same pan, halve the potatoes and gently fry in the lamb fat until nice and crispy.
Make the dressing, then gently toss the salad leave in it. On a large plate, start to assemble the salad by laying the baby gem on the plate, quarter the eggs and scatter all the remaining ingredients on top. Take the lamb, slice it on a board then lay it on top of the salad.