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.