Directions

1. Put cauliflower, shallot, stock, a pinch of salt, and 1 cup water into a medium saucepan. Bring to a boil; reduce heat, and simmer, stirring occasionally, until cauliflower is soft, 15 to 18 minutes. Working in batches, puree in a food processor, filling no more than 2/3 full each time. Season with salt and pepper. Cauliflower puree can be refrigerated up to 2 days; reheat over low heat until warm, stirring occasionally.
2. Preheat oven to 375 degrees. Toss Jerusalem artichokes in a medium bowl with about 1 teaspoon oil and a pinch of salt, separating rounds with your fingers. Spread on a rimmed baking sheet, and bake until light golden brown and crisp, 10 to 20 minutes, checking often and transferring slices to a plate as they brown. Set plate above or near oven to keep warm.
3. Stir together parsley, chives, and capers in a small bowl. Pour in remaining 2 tablespoons plus 2 teaspoons oil, and stir. Sprinkle with 1/2 teaspoon salt; season with pepper. Set relish aside.
4. Preheat broiler, with rack 6 inches from heat. Lightly brush a rimmed baking sheet with oil. Add scallops, and turn to coat. Toss with about 1/4 teaspoon salt and a pinch of pepper. Squeeze lemon over scallops. Broil until scallops are just cooked through, about 3 minutes. Spoon 1/2 cup cauliflower puree onto each of 4 plates, and top with 3 scallops. Drizzle with relish, and sprinkle with salt. Top with Jerusalem artichoke chips; serve.