Rinse the grape leaves and drain them in the colander. Peel the onion, dice very finely and fry in 2 tablespoons of oil until translucent. Stir in the rice and the coarsely chopped pine nuts and fry briefly. Fill up with 250 ml hot water and cook covered for 20 minutes. Stir in the chopped herbs. Season with salt, pepper, sugar and a little grated lemon zest.
Place the grape leaves with the shiny side down and spread 1-2 teaspoons of the rice mixture on top. Fold the leaf edges sideways over the filling and roll up from the base of the stem. Place the rolls side by side in a wide saucepan, season with salt and pepper. Pour the remaining oil and lemon juice over it and add enough water to cover all the rolls. Weigh down with a plate and cover and cook over a gentle heat for 40-60 minutes. Let cool down.