Clean and wash the spring onion and cut into fine rings. Rinse sprouts and let them drain. Mix mayonnaise, sour cream, spring onions and sprouts. Season with salt and pepper. Clean and wash the radishes and cut them into fine slices.
Pluck the lettuce leaves a little smaller, wash and drain well. Wash the steaks, dab dry. Peel, wash and roughly grate the potatoes and carrot. Mix with egg and flour, season with salt and pepper. Heat 3-4 tablespoons of oil in a pan. Fry the potato mixture in portions while turning to make 8 flat Rösti. Fry the steaks in another pan in 1 tablespoon of hot oil for 3-4 minutes while turning. Season with salt and pepper. Place salad leaves, radishes, steak and mayonnaise on each Rösti.
Heat 3-4 tablespoons of oil in a pan. Fry the potato mixture in portions while turning to make 8 flat Rösti. Fry the steaks in another pan in 1 tablespoon of hot oil for 3-4 minutes while turning. Season with salt and pepper. Place salad leaves, radishes, steak and mayonnaise on each Rösti. Place the second Rösti on top and serve