Pre-heat the oven to 400°F.
Place the meat in a bowl and season with salt, white pepper and the five-spice powder. Add the finely chopped scallions, grated ginger, grated garlic, breadcrumbs, egg yolk and sesame oil. Mix well and roll into small meatballs. Arrange on a baking sheet, drizzle with sesame oil and roast until brown and golden, 15-18 minutes.
Heat the vegetable oil in a soup pot. Add the mushrooms, sliced garlic, sliced ginger and chili pepper. Stir; add the soy sauce, water and stock and simmer to flavor. Wilt in the greens and cook to tender-crisp; combine with the meatballs.
Cool and store, then bring to room temperature and reheat to a low boil. Add the pasta and cook to al dente.
Serve in shallow bowls garnished with sesame oil and thinly sliced scallions.