Cut lamb and vegetables (onion, potato, carrot) into bite-sized pieces.
Heat oil in a pan and sauté the onions.
Add the lamb and stir-fry over high heat.
Add potatoes and carrots and continue to stir-fry together.
Add curry powder and water, and mix well.
Simmer over medium-low heat until the ingredients are cooked through.
Season with salt and pepper to taste.
Serve the curry over rice.