Arrange potato chunks onto an oven tray, drizzle with three quarters of the olive oil and season.
Roast for 30 minutes or until golden, turning occasionally.
Meanwhile, heat the remaining oil in a large frying pan and fry the onion until soft over medium heat.
Add the lamb mince and brown, then add the chopped tomatoes and stock; bring to a boil, then reduce to a simmer. Stir the harissa, season, then simmer gently for 20 minutes.
Remove the potatoes from the oven, spoon the lamb mixture over the potatoes, and sprinkle with feta, pomegranate seeds, coriander and mint before serving.