Place the corned beef in a slow cooker and add 10 cups of water with the cloves, juniper berries, cloves, coriander seeds and bay leaves. Set the timer on low for 8 hours.
When you are ready to make the rolls, preheat the oven to 375 degrees and bring a large pot of water to boil.
Prepare the cabbage leaves by gently peeling the leaves off. Lay the leaf flat on a cutting board with the thick stalk upward. Using a sharp knife, shave off as much of the thick stalk as you can without puncturing the leaf. This will allow the leaf to lie flat for stuffing and rolling. Boil the leaves for 2 minutes each to soften.
Chop the corned beef roughly. In a large bowl, combine it with the cooked rice, parsley, eggs, and a pinch of salt and black pepper. Stir together until the eggs are mixed well.
Gently take the softened cabbage leaf and lay it flat with the stalk side down. Take a handful of the corned beef mix and lightly place it 1/3 of the way up from the bottom of the leaf. Roll the bottom of the leaf up, then fold in the sides. Continue to roll the leaf together ensuring the stuffing stays stuffed inside. Place the roll with the seam side down in a large 9 x 13 baking dish. Repeat this process for each roll.
Warm 1 cup of tomato sauce with 1 cup of strained cooking liquid from the corned beef in a small pot. Ladle half of the liquid over the rolls. Bake for 20 minutes. Plate and serve with the additional cooking liquid if you like.