Fine chop an inch or two of the top end to add back in as visible asparagus, boil up the rest (add the cooking water from the tips if you boiled, or steamed them), blend and strain to extract the flavor, squeeze the pulp then discard it, then add the fine chopped Asparagus, simmer till reasonably tender then thicken, season and add other ingredients as desired, or if you are lazy simply add a packet of Asparagus soup powder.
You may want to cook one stalk with the tips to get an idea how much of the top end is soft enough to chop up.