8 baby bok choy ribs--ends trimmed, greens separated from stems
Directions
Make the dashi: In a large saucepan, add the kombu and cover with the water. Set aside to soak for 20 minutes. Set the saucepan over medium-high heat and bring to a simmer. Use a slotted spoon to remove and discard the kombu. Add the bonito flakes, reduce the heat to medium-low and gently simmer, stirring often, for 10 minutes, skimming off any foam that rises to the surface of the liquid. Turn off the heat and pour the dashi through a fine-mesh sieve set over a medium bowl. Rinse the saucepan and add the dashi.
Make the scallops: Set a large skillet over high heat for 2 minutes. Season the scallops with 1 teaspoon of the salt, add the grapeseed oil to the skillet, then place the scallops in the skillet, salted side down. Sear the scallops until they are golden-brown, 2 to 3 minutes. Turn the scallops over and sear the other side until lightly golden and the center of the scallops resists light pressure, 1 to 2 minutes longer. Add the butter to the skillet and, as the butter melts, spoon it over the scallops. Turn off the heat and transfer the scallops to a cutting board.
Return the skillet to the cooktop over medium heat. To the skillet, add the shallot and cook, stirring often, until the shallot is soft, 2 to 3 minutes. Add the mushrooms and ¼ teaspoon of salt to the skillet and cook, stirring occasionally, until the mushrooms are glossy, about 2 minutes.
Stack the bok choy leaves and roll them lengthwise into a tight cylinder, then slice them crosswise into thin ribbons. Slice the bok choy stems lengthwise into very thin pieces. Add the bok choy greens and stems to the skillet and cook until they are bright green and warmed through, about 1 minute. Season with the remaining ¼ teaspoon of salt and turn off the heat.
Bring the dashi in the saucepan to a simmer over medium-high heat. Turn off the heat and add the lemon slices, lime slices, orange slice, cilantro, parsley, thyme and scallions. Cover the saucepan and let the aromatics steep for 5 minutes. Pour the hot dashi into a fine-mesh sieve set over a medium bowl, using a rubber spatula to press on the solids, extracting as much liquid as possible.
Divide the shiitake-bok choy mixture among 4 bowls. Slice each scallop into quarters (so each scallop yields 4 small triangles) and divide among the bowls. Add the dashi-citrus broth to each bowl and serve.