Add shallot, garlic and red pepper flakes and saute until tender and fragrant. Add the washed and cleaned turnip greens. Mix together. Cook until they have wilted down, about 3 minutes. Add pepper to taste.
In a small bowl, whisk the Dijon mustard with the chicken stock. Add to the wilted greens and cook until the liquid has all but evaporated. Add the toasted pecans and serve immediately.