Put a large pan over a medium heat for 1 min. Add 1 tbsp olive oil and the lamb. Fry for 5 mins, turning once or twice, till the lamb is browned all over. While the lamb is browning, peel and finely slice the onion.
When the lamb is brown, lift it out of the pan and pop it in a bowl. Turn the heat down to low and add the onion with 1 bay leaf, 1 cinnamon stick and 2 tbsp water. Season with salt and pepper. Gently cook for 5 mins till the onion is soft and golden. If it starts to stick, add a splash more water.
While the onion cooks, peel and crush or grate the garlic. Finely chop the rosemary leaves. Peel and roughly chop the potatoes. Roughly chop the courgette.
Stir the garlic and rosemary into the onion with a pinch of chilli flakes (they're spicy, so use as much or as little as you like). Add the lamb back into the pan with any juices from the bowl. Add the potatoes and courgette.
Pour in the chopped tomatoes. Half-fill the can with warm water (around 200ml) and add to the pan. Crumble in the stock cube and add 1 tsp sugar. Cover, turn up the heat and bring to the boil.
Turn the heat down to medium. Simmer the stew for 25-30 mins till the lamb and potatoes are tender and cooked through. If it gets a little too thick, add more water. While the stew simmers, finely chop the chives.
Taste the lamb bredie and add more salt, pepper, chilli flakes or sugar if you think it needs it. Serve the lamb bredie in warm bowls, garnished with the chopped chives.