Preparation Preheat oven to 375°F. Place beets in roasting pan. Add 4 rosemary sprigs and enough water to barely cover beets. Cover pan tightly with foil. Roast beets until tender, about 50 minutes. Transfer beets to work surface. Peel while still warm; place on rimmed baking sheet. (Can be made 1 day ahead. Cover; chill.) Preheat oven to 350°F. Melt butter with oil in small saucepan. Pour over beets on sheet; toss to coat. Sprinkle with salt and pepper. Bake until heated through, stirring occasionally, about 20 minutes. Transfer to bowl. Garnish with additional rosemary sprigs and serve.
Preparation Preheat oven to 375°F. Place beets in roasting pan. Add 4 rosemary sprigs and enough water to barely cover beets. Cover pan tightly with foil. Roast beets until tender, about 50 minutes. Transfer beets to work surface. Peel while still warm; place on rimmed baking sheet. (Can be made 1 day ahead. Cover; chill.) Preheat oven to 350°F. Melt butter with oil in small saucepan. Pour over beets on sheet; toss to coat. Sprinkle with salt and pepper. Bake until heated through, stirring occasionally, about 20 minutes. Transfer to bowl. Garnish with additional rosemary sprigs and serve.