Preheat oven to 375 degrees. Pour 1/4 cup olive oil in a large pan with sides. You can use two 13×9 pans instead.

Peel parsnips, carrots and turnips. Coarsely chop all of the vegetables. I do not peel the sweet potatoes and red potatoes, but you can if you do not like the peels. Place all of them in the pan(s). Turn them over in the pan to evenly coat all of them. Sprinkle them with sea salt. Place rosemary on top, if using.

Roast for 25-30 minutes or until lightly brown, stirring midway. Cooking time may vary according to the thickness of the chopped vegetables.

Celeriac is very good in this. Rutabaga can be used in place of the turnips.