Place a non-stick frying pan over a medium-to-high heat. Spray with low-calorie cooking spray.
Season the lamb, and when the pan is hot, add the lamb and fry for a minute or two — until all sides are browned. Then remove from the pan and put to one side.
Lower the heat, spray the pan with a little more low-calorie cooking spray, then add the onions, carrots, and garlic.
Cook for 5 minutes — until the onions have softened.
Add the lamb back to the pan, then stir in the Ras el Hanout, tomato puree, chopped tomatoes, and stock. Bring to a boil, then cover with a tight fitting lid, and reduce the heat to a simmer. Cook for 15 minutes, until the carrots are soft and the lamb is cooked throughout. Preheat the oven to 180°C fan.
Stir in the lentils, honey, and lemon juice. If you think the hotpot is too saucy, continue simmering — uncovered — for another 5-10 minutes, to reduce the sauce and thicken.
Stir in the fresh herbs, and season the lamb with salt and black pepper if needed.
Pour into an ovenproof dish, and layer the slices of sweet potato on top.
Spray the top with low-calorie cooking spray, and sprinkle over a little salt and pepper. Place the hotpot on a baking tray to avoid spillages, then place in the oven. Cook for 35-45 minutes, until the sweet potato is fully cooked — it should be a nice golden brown colour. Then serve!