I'd never made plum roski, only nut. To make it less "leaky" I'd go with prunes rather than fresh plums.
I haven't checked on this line in awhile. But my version of halupke is a combination of my MIL's recipe (i.e., Slovak/Slovene), a woman I know whose mother was Polish, and experience.
First I look for a great, big, perfectly formed head of cabbage. Take a big stock pot and boil some water. Take my biggest meat fork and stab the head of cabbage (after removing the outer leaves), and immerse it in the boiling water. As each leaf softens, I peel it off and place on towels to cool.
Then I take a paring knife and "shave" the hard vein so that the cabbage leaf is uniform in thickness. At this point the leaf should be nice and pliable. No matter the rest of the recipe, this method of preparing the cabbage is what makes the dish ... plus makes it much easier to roll.
The meat can be any combination of ground meats; my mother-in-law used a combination of veal, lamb, and pork. My mother and her friends used just beef. But I will say beware of using just ultra lean meats, it can become rubbery when in a long-cooking dish as this is. For each pound of meat, one egg, and 1/8 cup of rice (raw). A small onion, a clove or two of garlic, a tsp of paprika (depending on your taste, sweet, hot or smoked, just what you like), salt and pepper.
Then, start rolling. And rolling, and rolling some more.
Put in a pot and cover with a combination of canned tomatoes (mom), stock (me), water (mother in-law) to cover. At this advanced age (55) I put in some packaged chicken stock and V8 to cover. Here's where there are differences. I love the addition a Polish friend told me, that is to say she takes smoked polish sausage and chops it into large portions (about 2") and tosses it into the pot. It really adds to the flavor. I like to put a lot (I'd say two tablespoons) of sweet paprika in the sauce (good stuff, by the way, not the stuff I still hear my sisters and mom say, "oh, it has no flavor, you just use it for the color"). Another friend (I can't remember which eastern European country she was from) adds a can of saurkraut at this point. But the main thing is that the cabbage should be covered with liquid.
Now, I grew up making these on top of the stove and since learned it is much easier to use my turkey roaster and put them (covered) in the oven (don't have to worry so much about the bottom burning). In both cases low heat for most of the day! I start doing this in the morning, put it in a covered roaster by noon, 350 and let it sit there all day (when it starts to bubble I turn it to 300 or even less),
If you like them mild, use sweet paprika. If you like it smoky, well, smoked. I add at least some hot paprika, because hubby and I like some heat.
My mom always served everything with potatoes, in this case mashed potatoes, with the "juice" poured over them like gravy. I think traditional is with egg noodles. A thinly sliced cucumber in an acidic vinagarette with some dill is a great accompaniment.
I know this "recipe" isn't exact ... the thing is, that these old home recipes never are. You have to do it and do it again and again. But this is a starting point. I developed mine over decades. Never thought much of cabbage rolls as a kid. But after I married (in my late 20s) and realized it was one of my husband's favorite dishes, I had my mother-in-law teach me to make it, then went to work on it with a vengeance, learning more along the way. I always reserve some of the "juice" for a shut in friend of mine who can really only eat soup. This is why the Polish smoked sausage really comes into play, it really makes the "juice" yummy.
