Bring a lot of water to a rolling boil. Remove the cabbage's center core and set it, core side down, in a pot of boiling water. For 10 minutes, simmer with a cover on.

While the cabbage simmers, warm the oil in a pan over medium-high heat and brown the onion and garlic for 3–5 minutes. Add the mushrooms and simmer for a further 2 minutes. Mixture should be poured into a big bowl to cool.

While moving the cabbage to a baking sheet with a rim, leave the water in the saucepan. With a tiny knife, carefully cut away from the core of the cabbage to remove the leaves. Cut off the thick spine in the center of the best 16 unbroken leaves to make rolling simpler. Put aside any remaining cabbage leaves that are damaged or small. (Return the core if it is too firm.

Set the oven to 350° F.

Add the meat, uncooked rice, parsley, tomato, salt, and pepper to the cooled onion mixture. Together nicely.

Roll up each leaf with about 1/4 cup of filling inside, set seam side down in a 13 by 9-inch pan. Rolls are covered in liquid, with some remaining leaves placed on top. Bake for 1 1/2 hours with foil tightly covering the pan. In case it drips, set the pan on a cookie sheet.

Remove from oven and allow to cool for at least 30 minutes before placing in the refrigerator for the night. (They thaw out wonderfully.)