Heat oil in the potjie pot over medium coals. Brown lamb pieces in batches until golden, then set aside.
Sauté onions and garlic until soft.
Return lamb to the pot and season with salt, pepper, rosemary, and oregano.
Add the carrots, potatoes, and butternut, layering vegetables neatly.
Pour in tomatoes, tomato paste, stock, and wine. Do not stir — let it cook in layers.
Cover with the lid and simmer gently over low coals for 2–3 hours until lamb is tender.
Add green beans in the last 20 minutes of cooking.
Serve hot with rice, pap, or fresh bread.