In the area where I live every 3rd Saturday of each month they have an big open market for all organic producers of the area. One of them is a potato farmer who grows over 10 qualities of potatoes, some quite rare. When it’s new potato season he brings all the qualities he has available and his wife bakes different dishes with each type of potato and you can try them in their stall. Once she had baked some potatoes with celery and I really enjoyed it. I decided to add young turnips because I love their taste and from time to time I go back to this mashed potatoes. —Maria Teresa Jorge
Yukon Gold potatoes peeled
3 + 2
young turnips, peeled
Extra Virgin Olive Oil - you won't use it all
Pre-heat the oven at 350ºF with rack in the middle.
Aromatic Olive Oil: In a small pan put the olive oil with 3 garlic cloves and the rosemary sprig and warm up. As soon as the garlic starts sizzling (they will still be completely white) turn off the heat and allow to infuse until completely cold - minimum 30 minutes. Set aside. You will only be needing 1/4 cup but it's very difficult to infuse such a small quantity of liquid.
Wash and trim the celery and peel the turnips. Cut in pieces of equal size and put in aluminium foil. Close tightly the aluminium and roast for 30 minutes in the oven.
Meanwhile, peel and cut the potatoes in 4. Put them in a pot with cold water, the garlic and the thyme. 15 minutes before the roasted vegetables are finished, bring the pot to a boil, season with salt and cook for about 10 minutes or until they are completely cooked.
Drain the potatoes in a colander and discard the 2 garlics and the thyme.
With a food mill, using the finest stainless steel disk, purée the potatoes, the celery and the turnip together into the empty pot.
Sieve the olive oil through a fine mesh sieve and put it in a glass container. You won't use all of it this time but it will soon disappear, you can use it in so many other dishes.
Put the pot with the vegetable mash over medium low heat, add the cream and stir well. Season with salt and Sechuan pepper and add about 1/4 cup of olive oil in a drizzle, stirring vigorously to blend all the elements.
Check again the seasoning and just before you serve, stir in the minced parsley. Serve hot drizzled with some garlic and rosemary infused olive oil.