Peel and wash the potatoes and cut or slice them into thin slices. Peel and halve the onion and cut into strips. Heat 1 tablespoon of oil in a saucepan. Fry the onion for 2-3 minutes until transparent. Deglaze with cream. Season well with salt and nutmeg. Fill potato slices into an ovenproof dish (approx. 21 cm Ø). Pour onion-cream over it. Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 40 minutes until golden brown
Meanwhile, clean the rocket. Wash the tomatoes and lettuce. Dab meat dry and season with salt and pepper. Heat 1 tablespoon of oil in a frying pan. Fry the meat on each side for 3-4 minutes on a high heat. Remove from the pan and wrap in aluminium foil. Roast tomatoes in the frying pan for about 1 minute at medium heat, season with salt and pepper. Remove from the pan
Cut out 4 circles from the gratin with a cutting ring (approx. 7.5 cm) and arrange on plates together with the steaks, tomatoes and salad