Step 1

Preheat oven to 350°F. Bring a large pot of water to a boil over high heat. Carefully remove 12 cabbage leaves, taking care not to tear them (reserve remaining cabbage for another use). Add the leaves to the boiling water; cook, stirring occasionally, until wilted, 8 to 10 minutes. Using a slotted spoon, transfer the leaves to a wire rack set inside a rimmed baking sheet. Let cool until easy to handle, about 5 minutes. Using a knife, trim and discard the thickest part of the main vein from the bottom of each leaf.

Step 2

Combine tomato sauce, brown sugar, vinegar and 1/4 teaspoon salt in a medium bowl.

Step 3

Place ground beef, rice, onion, pepper, 2/3 cup of the tomato sauce mixture and the remaining 1/2 teaspoon salt in a large bowl. Using your hands, lightly work the mixture until just combined. Spread 1/2 cup of the remaining tomato sauce mixture in the bottom of a 7-by-11-inch baking dish.

Step 4

Arrange 1 cabbage leaf, vein-side down, on a work surface with vein running perpendicular to the edge. Scoop 1/3 cup beef mixture onto the trimmed side of the leaf. Shape the beef mixture into a 2-inch log running parallel to the work surface edge. Fold the outer sides of the leaf over the filling and in toward the center. Roll up the leaf, pressing it tightly around the filling. Place the cabbage roll, seam-side down, on the tomato sauce mixture in the baking dish. Repeat with the remaining cabbage leaves and beef mixture.

Step 5

Top the cabbage rolls evenly with the remaining tomato sauce mixture. Cover the baking dish with foil. Bake until an instant-read thermometer inserted in the center of a roll registers 160°F, about 1 hour. Garnish with parsley, if desired.