2 tablespoons chopped flat leaf parsley, to garnish
steamed rice, to serve
Heat a frying pan until hot, then add half the butter. When foaming, add the red onion and fry for 2–3 minutes or until just softened. Add the mushrooms, tomato purée, mustard, pink and green peppercorns and paprika and fry, stirring, for a further 1–2 minutes. Pour in the beef stock and bring to the boil, then reduce the heat to low and simmer for 1–2 minutes.
Meanwhile, heat a separate frying pan and add the remaining butter. Season the beef. When the butter is foaming, add the beef and cook, stirring, for 2–3 minutes or until browned all over.
Add the soured cream and beef to the onion and mushroom mixture and mix well, then season to taste.
Spoon into warm bowls, scatter over the parsley and serve with steamed rice.