It's a very simple dish, but it's all about the timing. Get it wrong and you'll have a hard boiled egg and floppy asparagus, get it right and you'll have a rich, runny egg yolk to dip your perfectly done spears in to.
I found that my duck egg took about 7 minutes and 50 seconds in boiling, salted water to have a solid white, but runny yolk. If you can't get duck eggs, try hens eggs. My perfect boiled egg takes 5 minutes and 15 seconds in boiling water.
The asparagus takes 6 minutes to steam to perfection. Season the asparagus with salt and pepper, squeeze over a little lemon juice and dip into your duck egg yolk. Enjoy immediately!