Preheat the oven to 350 °F/180 °C.
Bring a large pot of water to a boil and cover.
Meanwhile, use a small sharp vegetable knife to remove the heart from the cabbage. To do this, cut a circle at an angle around the heart of the cabbage. Shred the heart of the raw cabbage and mix it with the stuffing. Discard the outer leaves that are browned or damaged and detach 12 leaves of the cabbage. With a knife, shave the spine thin of the leaves. Add the leaves to the boiling water and cook (blanch) until softened for 2 to 4 minutes. Work in batches as needed.
While the cabbage leaves are blanching, place a large bowl of ice water next to the pot. Using tongs, transfer the leaves to the ice water. This helps to harden the cabbage leaves. Drain and pat dry. Let cool.
To assemble, place 3 tablespoons to ¼ cup stuffing mixture in the center of each sheet. Roll by folding the sides firmly. Secure with toothpicks. Repeat the process until all the stuffing mixture is used up. Put aside.
In a 9 x 13-inch baking dish, spread tomato sauce. Place the rolls on the sauce in a row, seams down and cover with more sauce. Add pepper.
Cover with foil and bake for 20 minutes.
Uncover and leave under the grill (broil) for 5 to 7 minutes to brown the top. Garnish with parsley.
Serve 2 or 3 rolls per person with the tomato sauce and serve with quinoa, mashed potatoes or green salad.