Sausage and chorizo goulash

Name: Sausage and chorizo goulash
Ingredients: 1 tbsp vegetable oil; Knob of butter; 700g/1½lb good quality beef sausages, chopped; 300g/10½oz spicy chorizo sausage, chopped; 2 onions, finely sliced; 1 garlic clove, chopped.; 2 tbsp plain flour; 1 tbsp smoked paprika; 2 red chillies, finely chopped; 1 red pepper, finely sliced; 200ml/7fl oz beef stock; 175ml/6fl oz soured cream; 1 tbsp chopped fresh parsley; Cooked long-grain rice, to serve