Preheat your oven to 350F.
Fill a large pot with water and place it on the stove on high heat to bring to a boil.
While you are waiting for the water to boil, peel and chop the turnips.
Once the water is boiling, add the chopped turnip and turn the heat down to medium. Boil the turnips until they are soft (~ 20 minutes).
While the turnips are boiling, peel and chop the apples into slices ~3-4 mm thick.
When the applies are sliced, put them in a bowl with the coconut sugar and cinnamon and toss until the apples are well coated. Set the bowl aside.
When the turnips are soft, drain all the water from the pot. Then add the coconut oil and salt and mash the turnip until smooth (you can use your immersion blender to do this as well).
In a 2.5 quart casserole dish, layer the mashed turnips and apple slices, starting with the turnip layer. You should have enough for 2 layers of each.
Place the crust ingredients in a bowl and mix with a pastry blender or fork.
Place the crust over the final apple layer and cover the casserole dish with the lid. Bake for 60 minutes.