1 pound wild dry sea scallops
4 tablespoons unsalted butter
1 tablespoon unbleached all-purpose flour
1 cup whole milk
Kosher or sea salt
1 bunch spring onions, about 1/2 lb.
2 tablespoons fresh tarragon leaves
grapeseed or other neutral oil
2 tablespoons cr?me fraiche
fresh chives for garnish
Place the scallops on a plate or platter and refrigerate, uncovered, for 30 minutes.
Trim the spring onions, separating the green tops from the small bulbs. Dice the bulbs and roughly chop the greens.
Melt the butter in a saucepan over medium heat. Add the chopped spring onion bulbs and a pinch of salt, reduce the heat to low, and cook 20-25 minutes, until very soft. Add the green tops, toss through, and cook an additional 5-10 minutes until soft but still bright green. Sprinkle the flour over and cook for a minute or two, just until the raw flour smell is gone. Add the milk, raising the heat to medium, and cook briefly until thickened. Add the tarragon leaves and stir through, then turn off the heat and pour the mixture into a blender. Puree until very smooth, then return to the pan over low heat, cooking until the mixture is thick enough to coat the back of a spoon.
Pour a thin film of grapeseed oil in the bottom of a saut? pan and warm over medium-high heat until shimmering.
Carefully add the scallops a few at a time, being careful not to crowd the pan, and sear them just couple of minutes per side until they are nicely browned and caramelized – they should release from the pan easily once they?re ready, and they should still be a little jiggly in the middle, as they will continue to cook off the heat. Set aside and keep warm.
Taste the sauce and adjust salt if necessary. Whisk in the cr?me fraiche off the heat until the mixture is smooth, then spoon a little of the sauce into the bottom of shallow, warmed bowls, place scallops on top, and garnish with fresh chives.