For dried lentils, soak them in around 500ml water overnight. For dried chickpeas and beans, soak each separately with 1 teaspoon (7g) salt in around 500ml water overnight as well.
The next day, drain and rinse the lentils and set aside. Drain and rinse the chickpeas and add them to a pan with 1.5l of water. Bring to a boil, skim off any foam, then reduce the heat and simmer with a lid left ajar for 30 minutes. Drain, rinse and add the kidney beans and simmer for 60 minutes more, then drain both and set aside. 25 minutes before the legumes are done, you can start with the next step. If using canned legumes, simply drain and rinse and set aside.
Wash and drain the cabbage leaves and set aside as well.
Heat the oil in a large frying pan. Peel and finely chop the onions and sauté in the oil until they begin to turn golden (10-12 minutes). Stir in the tomato and red pepper paste and cook for another minute. Turn off the heat.
Meanwhile, trim and discard the lower stems of the parsley and dill and finely chop the rest, refrigerating a quarter of the chopped dill as a garnish later on. Add the chopped herbs, bulgur, rice, lentils, chickpeas, red kidney beans, spices, dried herbs and the remaining 1 teaspoon (7g) of salt to a large bowl. Tip in the cooked onions, then give it a good stir to mix everything evenly.
Set aside the larger cabbage leaves and use the ripped or very small ones to cover the bottom of a large casserole. Keep any leftover leaves for later. To stuff the larger leaves, place one on a clean work surface, trim off the thicker part of the stem and add 2-4 heaped tablespoons (depending on the size of the leaf) of the filling to the middle of the leaf. Fold the lower end over the filling, followed by the sides. Finally, roll it tightly towards the top to close it.
Place the stuffed cabbage roles in the casserole so that they fit snuggly over two layers and squish the prunes and leftover leaves in-between any gaps. Place a plate directly on top of the cabbage rolls to hold them down, then add 1l of water or enough to just submerge the plate. Bring to a boil, reduce to a fast simmer, cover with a lid left slightly ajar and cook for 45 minutes.
Turn off the heat, remove the plate, then cover again with the lid left ajar and leave to cool for 1-2 hours, or overnight. You can also serve them warm, if you like.
Arrange the cabbage rolls on a platter together with the prunes, then sprinkle with the remaining dill and serve.