Low-Carb Faux Potato Soup
2 cups whole milk 2 green onions, sliced, or more to taste 2 tablespoons olive oil, or more to taste 2 teaspoons salt, or to taste 3 pounds turnips, peeled and cubed 3 tablespoons cornstarch 4 cups chicken stock, divided 4 leeks, white portion only, thinly sliced 4 stalks celery, sliced 6 strips cooked crispy bacon, or more to tast… water to cover ½ teaspoon ground black pepper, or to taste