In a large saute pan over medium-high heat, add the oil. Once heated, add: ground beef, onions, rice and garlic and saute until the hamburger has browned. Remove from heat; stir in parsley, dill, salt, pepper and oregano. Set aside to cool a bit.
Place grape leaves in a bowl and pour water over leaves. Soak for 15 minutes and drain. Transfer leaves, dull-side down, to paper towels to dry.
Preheat oven to 375 degrees F.
Stuff grape leaves using 1 heaping tablespoon mixture in center of the dull-side of the leaf and fold outer parts toward the center; and roll up like you would a burrito. Do not roll too tightly. Arrange rolls in side by side layers in a deep baking pan. Once complete, fill the pan with water to the top of the grape leaves and place the butter on top. Cover with foil and bake 1 hour or until the water has been absorbed by the grape leaves.
To make the lemon sauce:
In large pot bring chicken broth to a boil, reduce heat and add cornstarch slurry so it has a consistency of gravy. Have egg whites you have whipped up in a large bowl and add gravy to them slowly folding in. Be careful not to cook the whites, only temper them. Whip until you have a creamy consistency and add in lemon juice. For that lemony flavor may have to add more lemon juice to get the right lemon flavor.
Plate up the grape leaves, and pour sauce on top. Should be off the hook.