Bring a large pot of salted water to a boil. Remove the core from the cabbage and carefully place the head into the boiling water. Cook for 3 minutes, gently peeling off softened leaves as they loosen. Set leaves aside to cool and trim thick veins if needed.

In a large bowl, combine ground beef, cooked rice, onion, garlic, egg, salt, black pepper, and paprika. Mix gently until just combined.

Place about ⅓ cup of filling near the base of each cabbage leaf. Fold in the sides, then roll tightly from the bottom up like a burrito.

In a bowl, mix tomato sauce, diced tomatoes if using, sugar, and a pinch of salt and pepper.

For the oven method, preheat oven to 350°F (175°C). Spread a thin layer of sauce in a baking dish, arrange cabbage rolls seam-side down, pour remaining sauce over the rolls, cover tightly with foil, and bake for 90 minutes.

For the stovetop method, place rolls in a large pot, cover with sauce, and simmer gently for 75 minutes.

Let rest for 10 minutes before serving. Spoon extra sauce over the top.