Add the water to a large Dutch oven and bring to a boil. Add the peanut butter and simmer for 20 minutes. Cool and remove any fat floating on the surface.
Meanwhile saute the lamb in the peanut oil until golden brown then add the onions and cook until onions are translucent. Add the garlic, thyme, powdered shrimp and season with salt. Stir to mix then add the carrots and cabbage.
Saute 3 minutes then add mixture to the peanut butter and water mix. Bring to a boil, reduce to a simmer and cook for 20 minutes. Add the sweet potato and cook for a further 40 minutes, until the vegetables are tender. Serve on a bed of rice.