Preheat oven to 190 degrees C. Grease a 20x30cm baking dish.
Bring the rice and water to a boil in a saucepan over high heat. Reduce heat to medium-low, cover and simmer until rice is tender and the liquid has been absorbed, 20 to 25 minutes. Allow rice to cool slightly.
Meanwhile, bring a large pot of water to a boil. Remove the core from the cabbage and place cabbage in the boiling water. Remove the outer leaves as they soften. Set leaves aside.
Heat butter in a frypan over medium heat and cook and stir the onion until softened and translucent, about 5 minutes. Stir together the cooked onion, chicken mince, cooked rice, eggs, garlic, salt, pepper and marjoram in a bowl.
Place about 1/4 cup of the meat mixture in the centre of each cabbage leaf. Roll leaf and tuck ends in to enclose filling. Secure each roll with a toothpick if necessary. Place rolls into prepared baking dish. Pour tomato sauce over the rolls.
Bake, covered, in the preheated oven until the meat in the rolls is no longer pink, 45 to 60 minutes.
This recipe is great with chicken mince, pork, beef, or turkey.