4 cups assorted root vegetables, such as parsnips, carrots, rutabagas, sunchokes and celery root (peeled and cut into 1/2-inch cubes or slices)
2 tablespoons unsalted butter
1/2 cup chicken or vegetable stock
2 teaspoons Sugar
1/2 teaspoon Sea salt
  Freshly ground black pepper (to taste)
2 tablespoons chopped fresh chives (for garnish)