Thinly slice the onion and garlic.
Peel the sweet potato then chop it into small cubes.
Chop the carrot and red pepper too.
Heat the oil in a large, shallow pan.
Gently sauté the onion for 5 minutes, then add the garlic, carrot, red pepper and sweet potato pieces.
Stir for a minute, then add the cumin seeds, oregano, chilli flakes and paprika.
Roughly chop the tomatoes, then add to the stew, including their juice.
Stir, then add enough water to cover everything well.
Add the stock cube and bay leaf.
Bring to the boil, then simmer for 10 minutes.
Add the chopped lamb pieces and the broad beans.
Cook for another 5-8 minutes, then serve with mint leaves scattered on top.