Brush the asparagus spears clean under running water. Peel them starting from the tips. Cut the lower ends into small pieces, provided that they are woody. Boil the peels and the waste pieces just covered with water for 15 minutes. Pour the peel stock through a sieve into the pot. Add the stock cube as well as the butter.
Cook the asparagus spears for 20 minutes at low temperature. Remove the asparagus spears with a slotted spoon, season with salt and pour the vinegar over them a few times. Then pour the oil over them.
Leave to marinate for half an hour, pouring the marinade over them from time to time. Drain the marinade, mix 4 tbsp. of it with the egg yolks and pour over the asparagus. Serve the asparagus salad sprinkled with fresh herbs, still lukewarm.
Our tip: As an alternative to fresh herbs, you can also use frozen ones – these are also characterized by a fresh taste!