Sweat the chopped onion in the lard until translucent, take it off the heat, and stir in the paprika so it doesn't burn.
Return to the heat, add the diced pork, salt it, and cover and simmer over low heat for about 30 minutes, stirring occasionally.
Add the well-squeezed sauerkraut, mix in, and continue simmering, covered, for another 30-40 minutes until both the meat and cabbage are tender - adding a little water now and then so it doesn't catch.
Once the cabbage is tender, mix the flour with the sour cream and tomato paste in a small bowl until smooth.
Stir this mixture into the dish, bring to a boil, add pepper, but only let it boil for a couple of minutes so the sour cream doesn't curdle.
Let it rest a few minutes before serving so the flavors can meld.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.