Warmth 2 Tbsp. oil in a big pot. Cook dinner remaining mushrooms, stirring often, till browned, about 5 minutes. Switch to a plate; wipe out pot. Warmth 1 Tbsp. oil in pot; cook dinner corn and beans, stirring often, till tender, about 5 minutes. Switch to plate. Scale back warmth to medium; warmth remaining 1 Tbsp. oil in pot. Cook dinner shallots and remaining ginger, stirring, till softened, about 2 minutes. Return mushrooms, corn, and beans to pot and toss to mix, then toss in noodles. Add cashews, coconut, and reserved sauce and cook dinner, tossing, till noodles are coated in sauce and warmed by, about 1 minute.