Prepare the cabbage by cutting out the tough middle bit (see photo above). Place the cabbage in a large pot filled with about 5-6 cm of water (cut end down), cover and bring to boil. Lower the heat and simmer gently for about 10 minutes, covered, until the outer leaves start separating. Remove the cabbage from the pot (use 2 forks and a knife to help the leaves separate) and carefully place the loose leaves on a plate one by one. Put the cabbage back in the pot, continue simmering, then remove a few more leaves. Repeat this process until you’ve got about 20 leaves.
Whilst the cabbage is simmering rinse the rice thoroughly, combine with 1 and ¼ cup of lightly salted water, cover and bring to the boil. Lower the heat and simmer for about 10 minutes, covered, until all the water has been absorbed. Place in a large bowl and set aside to cool completely.
In a frying pan heat up the oil, add the onion and cook over a low heat for about 5-6 minutes until softened and golden. Combine with the rice and set aside.
Preheat the oven to 350 F/ 180 C/ gas mark 4. Line a large casserole dish with cabbage leaves (the small ones or ones that have torn) and set aside.
Using a sharp knife slice off the thick bit running along the length of the cabbage leaf on the outside (see photo). Be careful not to split the leaf. Do this for each leaf.
Combine the rice and onion mixture (once cooled) with the meat, about 1 teaspoon of fine sea salt, add plenty of pepper and stir thoroughly.
Make a good size oval shaped meatball and place in the leaf. To make a cabbage roll fold in the longer sides, then wrap the filling starting with the thick end of the leaf. Press the mixture in with your fingers as you are rolling and roll as tightly as possible. Place the cabbage rolls one by one in the casserole dish so they are nice and snug, very close together.
Make the sauce by combining the hot stock with the passata and tomato paste and stirring thoroughly. Pour this mixture over the cabbage rolls. Cover with a sheet of non-stick paper cut to fit the shape of your dish (or small leaves if there are any left), then cover with a lid or tin foil and bake in the centre of the oven for 1.5 hours. Remove from the oven and enjoy!
Use the larger leaves to make your cabbage rolls and reserve the smaller ones for lining the oven dish (and covering the cabbage rolls, if there are any leftover, alternatively use non-stick paper).
Wrap the stuffing in the leaves as tightly as possible and place the cabbage rolls one by one in your dish very close together. The end bit of every cabbage roll should be facing downwards.
You can prepare the ingredients in advance. You can cook the cabbage and prepare the leaves ahead and once cooled completely, cover and refrigerate. Remove from the fridge 30 minutes before making the cabbage rolls to bring them up to room temperature. You can also cook the rice ahead and, once cooled, refrigerate until you are ready to make the recipe.
How to serve cabbage rolls: Traditionally Polish cabbage rolls are served with mashed potatoes, but you can also serve them as they are without any sides.
Freeze in a single layer in batches in an airtight container. Defrost in the fridge overnight and reheat in the microwave.