Tony Sargeant says that when you have trimmed of the scales along the bottom two thirds of the stalk and then snapped off the base to remove any ‘woodiness’ in the base. Keep and use the trimmings to make soup.
Sweat-off some finely chopped onion in butter. Then with a sharp knife thinly slice the trimmed end (from which the scales have already been removed when preparing the whole stalk) until you start to feel any ‘woody’ resistance then discard. Add the thin cross-sections to the butter and onions and cook down until tender. Add a splash of white wine, reduce, add some stock (chicken or vegetable), season and then liquidise. The result is delicious garnished with a few cooked asparagus tips.