COOK sunchokes in a pot for sunchoke purée, in milk, covered, over medium heat until soft, about 20 minutes. Purée all the ingredients, except salt and pepper, in a blender. Season with salt and pepper and keep warm in pot on very low heat.
MELT butter in a pan over medium heat, for wilted spinach. Add and lightly warm spinach, uncovered, until wilted, about 4 minutes. Season with salt and pepper. Keep warm.
DRESS sunchoke slices and scallion for walnut salad with lemon juice, lemon zest, and walnut oil. Toss in walnuts. Season with salt and pepper and set aside.
ADD canola oil to a pan over medium-high heat for scallops. Season scallops with salt and pepper and sear in hot pan for about 3 minutes. When brown, flip over and add butter. Baste scallops in the melting butter for 30 seconds. Remove from heat and set aside for plating.
PLACE Sunchoke Purée and Wilted Spinach on a plate. Add the Scallops and Walnut Salad and finish with toasted walnuts.