Dutch Oven over medium heat. Add butter, green garlic (or leeks) and onions and season with salt. Cover and cook until soft, about 8 minutes. 2. Stir in the potatoes and cook for 2 -3 minutes to warm. 3. Add water and buttermilk. Bring to a boil and simmer until potatoes are completely soft, about 25 - 30 minutes. 4. Mash soup with potato masher or a strong wire whisk until chunky. Thin soup with additional water or buttermilk, if needed. Adjust seasoning with salt and pepper. Stir in parsley. 5. Serve soup with dollop of Creme Fraiche and a drizzle of oil.