You know it's spring when asparagus starts showing up at the market. Actually a member of the lily family, asparagus is one of those eagerly awaited-for spring vegetables, traditionally available from February through June.
Stalks harvested toward the start of the season are often the most prized, as they are the first stalks to shoot from the plant and tend to be the most tender; asparagus harvested late in the season or out of season (often shipped in from elsewhere) can be woody and flavorless.
When shopping for asparagus, look for firm stalks with tight heads and good coloring (white asparagus is grown out of sunlight to keep the stalks from coloring). As for thick or thin stalks, it's really up to only you and what you prefer -- they're both fine.
To prepare asparagus for cooking, trim the woody base (2 to 3 inches) at the end of the stalk (some people prefer snapping the stalks -- I don't do this because the break often occurs too high on the stalk and you lose some good with the bad). Peel thicker stalks to remove the heavy skin; thin stalks are tender enough and do not need to be peeled.