My Mom used to make cabbage rolls for special holidays. They were always present for Thanksgiving and Christmas. My sister and I never cared for the cabbage when we were kids (being kids... after all, it was green) but it was a needed ingredient for the cooking.
This is the process I use and you are welcome to try it and pass it on. The important thing is to use plenty of liquid and easy on the rice. No one likes a dry cabbage roll. Really.
For one large roaster (or for two batches in the crock pot, use extra liquid) I use the following ingredients.
1 - family/bulk pack of hamburger. I use lean but regular works as well.
2 - heads of cabbage
2 - cups vinegar (approx)
1 - can of tomato juice, large
4 - cans tomato soup
2 - cans of diced tomato, 540 oz. (I like aylmers accents with green pepper and onion but any kind will work.)
1 - large onion, chopped up fine
Long grain rice (or instant or whole wheat or whatever your family uses)
Pepper (and garlic powder if your family likes garlic; we put it in everything here)
Put the hamburger in a large bowl and add the onion, one can of tomato soup, one can of diced tomatoes, and rice. I use enough rice so there will be about 1/3 rice to 2/3 meat once the rice cooks and expands. Don't be crazy with the rice. I maybe use two cups or so maximum (this is an estimate since I just pour it in until it looks right). Mix it all up well with some pepper and garlic seasoning and set aside.
The cabbage needs to be boiled and softened. Some people like to use sour cabbage but not everyone likes this flavor. I have found that boiling the cabbage in water with about a half cup of vinegar to soften it, does not exactly sour the cabbage truly, but it does remove much of the bitterness that some people associate with cabbage.
The core of the cabbage can be partially cut out of the cabbage or leave it there to use as a handle of sorts.
Boil the cabbage in a large pot, adding about half a cup of vinegar to the water. As the outer leaves soften, remove them and set aside to cool and dry some. You will need to be patient and let each layer have time to soften in the boiling water as it's exposed. About halfway through the cabbage, add more water and vinegar if necessary.
Don't try to overfill the pot if the cabbage is large. Use tongs and roll the cabbage occasionally to soften it all around. If you overfill the pot, it's going to splatter and you'll have a hot water swimming pool across your stove top.
In a large roaster, spread a can of tomato soup. Lay the first outside, softened cabbage leaves across the bottom of the pan in the tomato soup to form a one-leaf layer. This will protect your bottom layer of cabbage rolls from burning. It is also the best use for the very large outside leaves. Lay another can of tomato soup across the leaves and spread it around. Your pan is ready for the first layer of rolls.
Use the last can of tomato soup and the can of diced tomatoes and mix them together. This tomato mix will be added to each cabbage roll. About a teaspoon full or so.
Take a softened cabbage leaf and shave some of the spine of the leaf off, thinning it with a sharp knife. Try not to make a hole or slice it. As you get closer to the center of the cabbage, you may need to do this with some of the ribs on the leaves as well, not just the spine of the leaf.
Place the cabbage roll into the roaster along the edge. Each roll will be tucked up close to the one beside it. This will help hold them together as they cook.
Once you have one layer finished, cover in tomato juice until the layer of rolls is just barely covered and all the holes are filled in.
Add the second layer. At some point you will need to start the second head of cabbage, using the last of the vinegar with it.
When the second layer is finished, cover with the remaining tomato juice. Cook the whole works for a couple hours at 350. Reduce heat to about 325 and cook another hour or so. They can be eaten immediately or kept and reheated. They also freeze really well. I like to add a can of tomato soup on top of mine for heating if they've been frozen.