Sauté onions in olive oil - until transparent but do not brown. Remove from heat.
Add rice, salt and pepper, juice of one lemon and ½ cup water; stir. Add parsley and allow to cool.
Wash grape leaves to remove brine. Remove any stems. Place a tablespoon to a tablespoon and a half of the rice and parsley filling crossways onto the bottom end of each grape leaf. Fold stem-end over, then fold sides over partially covered filling then roll loosely.
Line the bottom of 2 ½-quart covered pan with the left-over grape leaves. Place rolled grape leaves with the filling, seam side down, onto the bottom of the pan. Arrange in layers. Add ½ cup water then drizzle additional teaspoon of olive oil over the rolls. Squeeze the juice of the remaining lemon over the rolls.
Cover, bring to a boil and the reduce heat and simmer for approximately 1 hour.