As long as you know how to cook scallops, this recipe is fairly straightforward. Don't let the tempura-fried Brussels sprouts scare you, they're pretty easy to make at home as well.
For the parsnip purée, combine the diced parsnip, crushed garlic, and heavy cream in a medium saucepan over high heat and season with salt to taste. Bring to a boil and cook over moderately high heat until the parsnips are tender, about 15-20 minutes. Drain the parsnips and purée with the butter. Season with salt and pepper to taste and keep warm until ready to plate.
For the tempura batter, combine the rice flour and a pinch of salt in a bowl. Add the egg white and whisk to incorporate, then slowly whisk in the ice water until a wet yet nape consistency is reached. Set aside to rest.
Heat the olive oil in a medium sauté pan over high heat and season each scallop with a pinch of salt and pepper. Sear 4 scallops at a time in the pan until well browned on each side, about 1 minute per side. Do not try to sear more than 4 scallops at time, because overcrowding the pan will prevent them from browning well. Remove the scallops from the pan and set aside.
Pour the honey into the pan and stir. Let it caramelize for 1-2 minutes, and then stir in the lemon juice. Place the scallops back in the pan and turn to coat them with the honey glaze. Remove from heat and set aside.
While you are searing your scallops, heat the oil in a small saucepan until it reaches 340-360 degrees. To check if the oil is at the right temperature for frying, place a drop or 2 of the batter into it. If the batter bubbles to the surface right away, then the oil is hot enough. Place a handful at a time of Brussels sprouts leaves into the batter and stir well to coat, and then fry in the oil until light golden brown, about 10-15 seconds per handful. Drain on a paper towel and set aside.
To plate, place a large spoonful of the parsnip purée in the center of a plate, and then top with 3 or 4 seared scallops around the edge of the parsnip purée. Pour a bit of the honey glaze from the pan over each scallop, and then garnish with the tempura-fried Brussels sprouts in the center.