This one's a bit of an oddity - at least the way I make it. I use a very conventional method for the Hollandaise sauce - which can be made well in advance - and then microwave the asparagus.
First the sauce. You will need a thick old-fashioned basin, about 5 inches diameter, and a small saucepan into which the bowl will fit without resting on the bottom. (No one has those double-boiler saucepans designed for this task any more!)
In the saucepan, put two tablespoons of white wine vinegar - preferably tarragon vinegar. Add the same quantity of cold water. Add to the liquid a large dried bayleaf (or a fresh one from the garden) and four or five black peppercorns - these should be whole, not ground or crushed.
Boil up the liquid in the saucepan until about half has evaporated. (Don't let it boil dry!) Let the liquid cool slightly.
Separate an egg, discarding the white and put the yolk only into the bowl. Using a whisk, gently beat the egg yolk, then strain the vinegar from the saucepan into the bowl. Whisk up again.
Cut into lumps about four ounces of butter. The lumps should be about half-an-inch on a side.
Discard the bayleaf and peppercorns, and fill the saucepan about a quarter-inch deep with cold water. Place the bowl over the saucepan, and apply a low heat. The objective here is to get the water to bubble gently, rather than a fast boil.
While whisking the egg mixture, add the lumps of butter one or two at a time. The butter should melt and combine with the eggs to form a thick sauce. Once all the butter has been whisked in, remove the bowl from the heat and allow to cool. (This sauce is traditionally served luke-warm.)
The asparagus is easy. Wash a quarter of a pound of asparagus tips, and cut off any dried-out parts. Put in a microwave-safe dish, and add just a splash of water and the smallest pinch of salt. Cover the dish and cook in the microwave for about 4 minutes.
To serve, place the asparagus on two plates, and drizzle with a generous portion of the sauce. Crusty fresh bread works well with this, to sop up the remaining sauce.