Adapted from keyingredient.com
lb shiitake mushrooms, stemmed and sliced ¼ inch thick
medium leek, white and light-green parts only, halved lengthwise, rinsed well, and sliced ⅛ inch thick
Tbs extra-virgin olive oil
Kosher salt and freshly ground black pepper
skinless salmon fillets, 6 to 8 oz each
lightly packed cups (3 oz) baby arugula
Position rack in the center of the oven and heat the oven to 450 degrees. Line a large rimmed baking sheet with parchment. In a medium bowl, toss the mushrooms, leek, oil, 1/2 tsp salt, and 1/4 tsp pepper. Finely grate the lemon zest. In a small bowl, mix the zest with 1 tsp salt and 1/4 tsp pepper. Arrange the salmon on the baking sheet, rub the lemon zest mixture on the tops and sides of the fillets, and scatter the mushrooms and leeks around the fish in a single layer. Roast until the vegetables are tender and the fish is opaque in the center, about 15 minutes. If the fish finishes cooking before the vegetables, transfer it to a plate and continue to roast the vegetables until tender, 3 to 5 minutes more. Combine the arugula and roast vegetables in a large bowl. Squeeze about 1 Tbs juice from the lemon onto the vegetables and toss to combine. Season to taste with salt, pepper and more lemon juice. Divide the mixture among four serving plates. Top each salad with a piece of the fish and serve.