Preheat the oven: Preheat the oven to 350 degrees Fahrenheit.
Boil the cabbage: Bring a large pot of water to a boil and carefully place the whole cabbage in the water. Boil until the outer leaves begin to soften, about 10-15 minutes. You can also freeze the cabbage the day before and thaw it before using, which makes the leaves pliable.
Prepare the cabbage leaves: Place the cabbage in a colander to cool enough to handle. Cut out the core and gently peel away the whole cabbage leaves. If some leaves tear, that's OK. Double them up with another leaf or use the torn pieces to line the bottom of the pot.
Make the filling: In a large bowl, combine the ground beef, spices, chopped parsley, breadcrumbs, rice, and egg. Mix until everything is well combined.
Make the sauce: Add all of the sauce ingredients to a bowl and stir to combine. Taste and adjust with more brown sugar for sweetness or fresh lemon juice for extra tang.
Trim the cabbage leaves: Use a small paring knife to trim the thick stem from each cabbage leaf.
Fill and roll: Take about 1–2 tablespoons of the meat mixture and place it near the bottom of the cabbage leaf. Roll it up, tucking in the sides so no meat is exposed, then continue rolling into a tight cabbage roll.
Arrange the cabbage rolls: Line an oven-safe pot with any extra or torn cabbage leaves, then nestle the cabbage rolls into the pot.
Add the sauce: Pour the sweet and sour tomato sauce over the cabbage rolls, making sure they're well covered.
Bake: Cover the pot with a lid and bake for 50–60 minutes, until the meat is cooked through and the cabbage rolls are tender.
Serve: Serve the cabbage rolls with a spoonful of tomato sauce and extra lemon, if desired.