Beat the eggs and lemon juice in a metal bowl. Place 1 cup of water and a pinch of salt in a pot over medium heat. When the water begins to boil, turn off the heat.
Place the bowl with the eggs in it and whisk rapidly to make a sauce. Cut the lamb into pieces and rinse in cold water. In a pan over medium heat, add the oil, lamb and sliced onion, with a pinch of salt and pepper.
Lower the heat and turn the lamb frequently so that it does not brown. Cover and continue to cook, stirring often.
After about an hour, when the lamb is cooked through, pour the egg sauce into the pan to flavor so that everything is combined and cook for a few more minutes. Pour sauce over the lamb before serving.