Cook the potatoes in salted boiling water for 12 mins, or until softened. Drain well.
Add half of the oil to a nonstick wok and place over a medium-high heat. Toss in the garlic, spinach and beans, and stir-fry for 4 mins or until the spinach has wilted and the beans are piping-hot.
At the same time, heat the remaining oil in a heavy-based nonstick frying pan over a medium-high heat. Add the spring onions, peppercorns, mustard and vinegar, and heat for 2 minutes.
Add the steak to the peppercorn mix and cook for 2 minutes on each side for rare, 3 minutes for medium, and 5 minutes for well done. Remove from the heat and stir in the fromage frais and lemon juice.
Serve the steak with the potatoes and some sauteed vegetables.
*Inspired by Kelly N. featured in the Realfood Cookbook
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.