This elegant, simple recipe is perfect for special occasions and weeknight dinners alike. Briny-sweet scallops are quickly seared, then served on a velvety emerald swath of asparagus purée for springtime flare. Keep the asparagus tips intact for texture, and follow Michael Ruhlman's tricks to bring out the vegetable’s bright green hue.
Asparagus: Bring a medium pot of water to a boil. Salt the water generously (make it as salty as seawater). Trim the woody ends from asparagus and discard; then submerge asparagus in the boiling water. Cover with lid just until the water comes back to a boil, then uncover and cook until al dente (tender but with just a little crunch), 3–4 minutes. Meanwhile, prepare an ice bath by filling a large bowl with ice water.
Asparagus are done when they bend without snapping. Use a spider strainer to transfer them to the ice bath; submerge and stir to immediately stop the cooking. Reserve cooking water (to thin purée). Cut asparagus tips and reserve for garnish. Cut stalks into 2-inch pieces and set aside.
Place asparagus stalks in the blender and cover with lid; pulse a few times. Remove the smaller cap in the lid and turn blender to medium speed. Ladle in a slow stream of cooking water (about ½ cup) to help the asparagus purée. Use caution, as the water and purée are hot! Replace the cap, then purée on high speed. When the purée is smooth, strain through a fine-mesh strainer into a bowl to remove any fibrous strands. Salt the purée to taste and set aside.
Scallops: Place scallops on paper towels in an even layer and pat dry; this is an important step to get a nice sear. Pull off and discard any tough side-muscles (their fibers run against the grain of the rest of the scallop). Heat a skillet over medium-high heat, then add oil. (Add more as needed to coat the bottom of the skillet.) When the oil begins to ripple, add scallops in an even layer without crowding. Let cook undisturbed, 60–90 seconds. Scallops are ready to flip when they are evenly caramelized and no longer stick to the skillet. Before flipping, sprinkle with sea salt. Meanwhile, in a small saucepan over medium-low heat, warm the asparagus purée.
When scallops are golden brown on the first side, they should release easily from the skillet. Using a small offset spatula, flip each scallop to sear the second side; continue sautéing, 30–45 more seconds, depending on size. Remove scallops to a paper towel-lined plate and let rest while finishing the sauce.
Add half of the asparagus tips to the warmed purée. Add butter, then swirl the saucepan continuously until all the butter has melted and emulsified into the purée to make a rich sauce.
Immediately before serving, add the lemon juice to the asparagus sauce and stir to combine; taste and adjust seasoning. Divide the sauce among plates or large bowls, then place the scallops on the sauce. Garnish with remaining asparagus tips and serve immediately.