Instructions

1. Cut squash in half crosswise, separating the long neck from the round body. Cut body in half lengthwise, scoop out seeds, peel, cut into small cubes, and set aside. Trim stem from squash neck, cut neck into quarters lengthwise, and peel; slice each quarter crosswise into 1⁄4''-thick pieces, and set aside separately.
2. Put squash neck pieces and leeks into a medium saucepan. Add 1 cup water, and bring to a boil over medium-high heat. Gradually add 8 tbsp. of the butter, a few pieces at a time, and cook until squash is tender when pierced with the tip of a knife, 3-5 minutes. Season to taste with salt. Remove pan from heat, cover, and set aside.
3. Meanwhile, put squash cubes, the remaining 2 tbsp. butter, 1 cup water, and a generous pinch of salt into a medium saucepan, and simmer over medium heat until tender when pierced with the tip of a knife, 10-15 minutes. Drain; then mash with a potato masher or fork until smooth.
4. Heat oil in a large, heavy-bottomed skillet over medium-high heat. Pat scallops dry with paper towels, and season to taste with salt. Add to skillet, and sear on both sides until deep golden, about 30 seconds per side.
5. Divide mashed squash between 4 warm plates, put a quarter of the scallops over each, and spoon sliced squash with leeks and butter sauce over scallops. Garnish with snipped chives, Sichuan peppercorns, and chervil.