Place a large heavy pot over medium heat and melt the lard. Add the chopped onion and cook slowly for 8 to 10 minutes until soft and golden. Stir regularly so the onion sweetens without browning too quickly. Once softened, add the garlic and continue to the next step.

Remove the pot briefly from the heat and stir in the sweet Hungarian paprika and hot paprika if using. Mixing paprika away from direct heat prevents bitterness and preserves its rich red colour. Add the pork cubes immediately and return the pot to the heat for the next stage.

Cook the pork for 5 to 6 minutes, stirring often until the meat loses its raw colour and begins to take on a light golden edge. Season lightly with salt and black pepper. Add the caraway seeds and bay leaf before continuing.

Pour in the water or stock and scrape the bottom of the pot to release any caramelised flavour. Reduce the heat to low, cover with a lid, and simmer gently for 35 minutes. The pork should begin to soften while building a rich paprika broth.

Stir the sauerkraut into the pot, separating any tightly packed strands with a spoon. If the sauerkraut tastes especially sharp, rinse it briefly before adding. Mix thoroughly so the cabbage absorbs the paprika infused liquid.

Cover again and simmer gently for another 35 to 40 minutes, stirring occasionally to prevent sticking. The pork should become tender and the sauerkraut mellow while still keeping a pleasant bite.

In a small bowl, combine the sour cream and plain flour until smooth. Ladle in a spoonful of the hot stew liquid and stir well to temper the mixture. This keeps the sour cream silky when added to the pot.

Slowly stir the sour cream mixture into the stew and cook gently for 5 more minutes without boiling. The sauce should become creamy and lightly thickened. Taste and adjust the seasoning before moving to serving.

Ladle the stew into warm bowls and finish with an extra spoonful of sour cream if desired. Székelykáposzta is traditionally served with crusty bread or boiled potatoes to soak up the smoky paprika sauce. A scattering of fresh parsley adds brightness to the rich flavours.