Make the preserved lemon relish. Remove the lemon peel and finely chop the remaining fruit. Finely dice the shallot, and finely chop the parsley. Mix the chopped lemon, shallot, and parsley with salt and pepper to taste and set aside.
Cut the king oyster mushroom stems into large, scallop-sized pieces. Discard the caps or save them for a stock or separate dish. Using a paring knife, score a hatch pattern on both flat sides of the mushroom pieces.
Place a large, salted pot of water on the stove to come to a boil. Place the vegan butter in a large sauté pan over a medium heat.
Once the vegan butter is fully melted, put the mushrooms slices in the pan and sprinkle with salt and pepper. Let cook for 3-4 minutes per side or until golden brown and the scored lines are well-defined. Spoon the melted vegan butter over the mushrooms to baste them while cooking. Once they are fully browned on both sides, remove the pan from the heat and set aside while you cook the pasta.
Prepare the linguine according to package instructions. Once cooked, remove and toss with the olive oil.
Serve the dish by plating the pasta, placing a quarter of the cooked scallop mushrooms on top, then garnishing generously with the preserved lemon relish.