For the roast beef in the rocket nest, wash the rocket salad, dry it in the salad spinner and pluck it into small pieces. Peel and dice the onion.
Mix olive oil with raspberry vinegar, salt and pepper, stir in onion and marinate arugula with it. Arrange salad and roast beef on plates.
Sprinkle the roast beef in the arugula nest with parmesan shavings and serve.