How to Make It
Preheat the oven to 500°. Toss the turnips with 2 tablespoons of the olive oil and spread them out in a small roasting pan. Season with salt and pepper and roast, turning once or twice, until tender and golden in spots, about 25 minutes.
Meanwhile, in a large, deep skillet, boil the chicken stock until reduced to 2 cups, about 15 minutes. Add the butter, let it melt and keep warm.
In a large saucepan, cover the potatoes with cold water, season with salt and bring to a boil. Cook until tender when pierced, about 10 minutes. Drain the potatoes and return them to the saucepan. Cook over moderate heat for 1 minute to evaporate any moisture. Add the remaining 1/2 cup of olive oil to the potatoes and mash them with a potato masher. Season with salt and pepper and keep warm.
Return the stock to a gentle boil. Working quickly, add a few slices of pork at a time and cook until just pink in the center, about 30 seconds; using a slotted spoon, transfer the meat to a large plate. When all of the pork has been cooked, return it to the skillet. Add the turnips and toss. Serve in shallow bowls and garnish with the parsley. Pass the mashed potatoes alongside.