Start by placing the steaks between two sheets of cling film. Using a meat mallet or rolling pin, gently bash the steaks until they’re ½ centimetre thick.
Trim the flattened steaks of any excess fat, then slice thinly.
Place the steak in a bowl and season with salt, pepper, and the smoked paprika.
Over a medium heat, heat half the oil in a heavy-based pan. Add the shallots and gently soften for 10-12 minutes.
Add the garlic and mushrooms and cook for 6-8 minutes until the mushrooms soften.
Stir in the tomato paste and beef stock. Bring to the boil and reduce the heat. Simmer until the stock has reduced to about half.
Once the stock has been reduced, stir in the mustard and sour cream. Keep the sauce warm by covering the pan with a lid.
Meanwhile, heat another pan over medium-high heat and add the remaining olive oil. Add the beef slices and sear until browned evenly. You may need to do this in batches. Drain the beef and set aside.
Once all the beef is cooked, return all the slices to the pan. Stir in the sauce and simmer for a few minutes. Add salt to taste.
To finish, divide the beef among 4 warm bowls with long-grain rice. Top with freshly chopped parsley and diced gherkins.
