One good recipe with turnips and apples is a turnip bake. To make the recipe, preheat the oven to 350 degrees Fahrenheit. Peel and cube 1 large turnip, and add the cubes to a pot. Add enough salted water to cover the turnip. Bring the water to a boil, and then set the heat to medium-low. Cook the turnips until they are soft, about 15 to 20 minutes.
Remove the turnip cubes from the heat, and strain them. In a mixing bowl, mash the turnips with 1 pinch of salt, 1 pinch of ground black pepper and 2 tablespoons of butter until the turnips have a smooth consistency.
Peel, core and dice 2 large apples, and toss them in 2 tablespoons of brown sugar and 1 pinch of ground of cinnamon to coat them evenly. In a greased 8-inch casserole dish, layer half of the turnips, then half of the apples, then repeat the layers until all ingredients are in the dish.
Mix 1/4 cup of all-purpose flour with 1/4 cup of brown sugar and 2 tablespoons of softened butter until they form a coarse crumbly texture. Sprinkle the crumb mixture over the apples and turnips. Bake the casserole until it's bubbly and the apples are tender, approximately one hour.