An Asparagus Steamer is a very tall, narrow, cylinder-shaped, stainless-steel pot with a tall, narrow insert (or basket) that may be a mesh cage or more of a wired cage.
The pot will be about 9 to 10 inches (22 1/2 to 25 cm) tall, and about 5 inches (12 1/2 cm) wide. It will hold a single large bundle of asparagus.
The pot will have a lid, either solid metal, or glass. The glass is meant to be see-through, but they are often fogged over by condensation and steam. Consequently, some of the glass lids now have a few vents in them to prevent this from happening.
The pot’s insert will have a handle for easy lifting out.
To use, you fill the pot about 1/3 to 1/2 full with water. You bring the water to a boil, and stand your prepared asparagus in it upright, tip ends up. This ensures that the tougher ends of the stalks are in water, where they get boiled, and the more tender tips are out of the water, where they just get steamed. You may need to trim your asparagus stalk bottoms further if they are too tall for the pot with the cover on. Leave, however, more stalk on than you would normally when not using a steamer like this.
Let simmer about 7 minutes. Then, remove the asparagus, and with kitchen scissors snip a further inch (2 1/2 cm) off their bottoms. You can use the snipped-off stalk bits for soups.
Ones that come with wire cage (as opposed to mesh) let you empty the pot in the sink, then hook the cage onto a handle of the pot to let the cage rest there suspended for a minute or two while the stalks drain.