Boil the rice for five minutes, rinse under cold water, and drain.
Fry chopped onions in oil for three minutes, then add garlic and cook for two minutes.
Stir in both paprikas, salt, and pepper, cook for one minute, then transfer to a bowl to cool.
Boil 1.2 liters of water in a large pan and remove undamaged leaves from the cabbages.
Shave thin slivers off the thick central vein of each cabbage leaf to aid rolling.
Blanch cabbage leaves in batches in boiling water for five minutes, then rinse in cold water.
Dissolve the stock cube into the cabbage cooking water and set aside in a jug.
Mix rice, pork, parsley, and seasoning into the cooled onion mixture by hand.
Place pork filling on a cabbage leaf, roll once, tuck in sides, and secure into a parcel.
Layer parcels in a pan and pour over the chicken stock until almost covered.
Cover and simmer for 45 minutes until the pork and rice are cooked.
Fry sliced onions and garlic for the sauce until softened and browned.
Add tomatoes, purée, sugar, and 400ml water, then simmer for 25 minutes until thick.
Whisk four ladles of specialized stock into the tomato sauce and boil for 2-3 minutes to reduce.
Transfer cabbage rolls to a platter and pour the hot tomato sauce over them.
Top with soured cream and a sprinkle of paprika before serving.