Heat the lard in a heavy pot. Generously salt and pepper chicken and brown on all sides. Transfer to a plate.
In the same oil, add the onions and fry until golden brown. Add the garlic and tomatoes and fry another 2 to 3 minutes. Remove the pot from the heat and stir in paprika, salt and pepper. Be careful not to burn the paprika as it will become bitter if scorched.
Return the chicken to the pot and place it back over the heat. Pour in chicken broth. The chicken should be mostly covered. Bring to a boil, then cover and reduce heat to medium low. Simmer for 40 minutes. Remove the chicken and transfer to a plate.
In a small bowl, combine sour cream, heavy cream and flour. Stir the cream mixture into the sauce, whisking constantly to prevent lumps. Bring to a simmer for a couple minutes until the sauce is thickened. Add any additional salt and pepper to taste.
Return the chicken to the sauce and simmer to heat through. Traditionally, this is served with Hungarian nokedli (similar to German spaetzle.) Alternatively, serve with fresh cooked noodles.