Core the cabbage and carefully remove 12 large outer leaves, blanching them in boiling water 2–3 minutes each until pliable, or use the freeze-and-thaw method.

Combine ground beef, cauliflower rice, egg, grated onion, salt, and pepper in a bowl.

Place a portion of filling at the base of each cabbage leaf, fold in the sides, and roll into a tight bundle.

Whisk together crushed tomatoes, lemon juice, and sugar substitute in a large pot.

Arrange the cabbage rolls seam-side down in the sauce.

Cover and simmer 1 hour to 1 hour 15 minutes, until the cabbage is tender and the filling is cooked through.