Peel and quarter the potatoes. Cook in salted water for about 20 minutes. Wash the fillet, dab dry and cut into thick slices. Heat 2 tablespoons of oil in a pan and fry the medallions in it from both sides at medium heat for about 5 minutes.
Season with salt and pepper. Roast pine nuts in a pan without fat until golden brown. Remove from the pan and allow to cool. Peel garlic and chop finely. Clean, wash, drain and coarsely chop the rocket.
Drain the potatoes and mash them with a potato masher. Add stock and 3 tablespoons of oil bit by bit and stir in. Season with salt, pepper and nutmeg. Add garlic and rocket and fold in.
Sprinkle with the remaining olive oil and arrange on plates together with the medallions. Sprinkle with pine nuts and arrange as desired.