Apples add sweetness to this creamy, nutrient-rich puree.
Melt butter in a large straight-sided skillet over medium. Add onion, ginger, and apples; cook, stirring frequently, until onion begins to soften, about 3 minutes.
Stir in rutabagas, broth, and 1 teaspoon salt. Cover and cook, stirring once halfway through, until rutabagas are tender, about 30 minutes. Transfer to a food processor and puree until smooth. Serve immediately, topped with butter.