This is one of those recipes that only makes sense with local produce. When "sparrowgrass" (English dialect variation, courtesy of my husband) is in season we eat this at least once a week; for the rest of the year, we just dream of it. Measurements are approximate and depend on the thickness of your asparagus. But you should be left with whole, perfectly cooked spears, glazed with their butter-enriched juices. —ying
Place the asparagus in a single layer in a large saute pan. Add water to the depth of 1/3 the thickness of the stalks. Pop in the butter, sprinkle with a pinch or two of sea salt, cover the pan, and bring the water to a lively simmer.
Uncover the pan and cook the asparagus just until tender-crisp, turning the stalks once. When the asparagus is ready, you should have about 2 tablespoons of pan juices remaining. (If there is more, fish out the asparagus, keep it warm, and reduce the liquid accordingly.) Serve the sparrowgrass drizzled with its buttery juices.