To Prepare the Stuffed Cabbage. Preheat oven to 350F.
Fill a large stock pot about half way up with water, add a generous pinch of Kosher salt, and bring to a boil. Once boiling, use a spider or large slotted spoon to carefully place the whole cabbage into the stock pot. Cook until tender.
To the ground lamb, add the minced red onion, chopped fresh parsley, parboiled rice, raw eggs, Kosher salt, and freshly ground black pepper. Using your hands, thoroughly combine the mixture.
Form loose lamb meatballs the size of tennis balls and set aside on a sheet pan or plate. The mixture will yield about nine lamb meatballs.
Remove the tender cabbage leaves from the boiling water and place them directly into a large bowl of ice water to stop the cooking process. If any cabbage leaves rip during this process you can use them to line the bottom of your pan.
Carefully remove nine nice cabbage leaves to use for the stuffed cabbage, carefully removing any excess core with your knife. With the seam-side down, lay the lamb meatball mixture into the center of each leaf and roll into a package. Place each stuffed cabbage open side down into your pan.
Build the sauce for your stuffed cabbage by scattering your ingredients directly on top: sliced red onion, tomato sauce, and whole peeled tomatoes. Season with Kosher salt, freshly ground black pepper, light brown sugar, and finish with the freshly squeezed juice of one lemon.
Cover your pan with a tight fitting lid and place in a 350F oven for approximately one-hour to one-hour and twenty-minutes. During the cooking process the sauce will slightly reduce and the ground lamb stuffed cabbage will slightly expand.
Serve your ground lamb stuffed cabbage dressed with some of its rich juices for a truly delicious and elevated - yet traditional - meal.