How to Make It
Preheat the oven to 400°. In a mini food processor, puree the olives; transfer to a bowl. Using a sharp knife, peel the orange, removing all of the bitter white pith. Working over another bowl, cut in between the membranes to release the sections.
On a rimmed baking sheet, drizzle the turnips with 1 tablespoon of the oil. Roast for 20 minutes, until almost tender.
Meanwhile, in a large, deep skillet, heat the remaining 2 tablespoons of olive oil. Add the onion and garlic and cook over moderate heat, stirring occasionally, until softened, 5 minutes. Add the water and turnip greens, cover and cook over moderate heat, stirring occasionally, until the greens are just tender, 5 minutes. Season with salt and pepper.
Pour the orange juice over the turnips. Roast for 5 minutes longer, until the turnips are tender and glazed; season with salt.
Add the spinach to the greens; toss until wilted. Drizzle the pureed olives onto a platter. Top with the turnips, greens, orange sections and hazelnuts. Serve hot or warm.