I made this at Thanksgiving this year and I essentially just winged it (okay, when do I not?). It still turned out delicious, of course, and was a must share with all of you. Japanese sweet potatoes are by far my favorite sweet potatoes. They are the sweetest variety and I knew mixing them with the slightly more tart turnip would make for a good combo. The turnip balances the sweetness of the sweet potato and the creamy coconut milk sauce brings it all together.
Japanese Sweet Potato and Turnip Gratin
-2 large Japanese sweet potatoes
-1 can full fat coconut milk
-1/2 cup water
-2 tbs. coconut butter (alternatively you can use maple syrup, the sauce just won’t be as thick)
-1 tsp lemon juice
-2 tbs fresh thyme, finely chopped
-1 tbs dried sage
-1 tbs fresh rosemary,
-1 tsp cinnamon
-1/4 tsp. salt
-1-2 tbs. tapioca or arrowroot starch
Preheat the oven to 375 F.
Peel your sweet potatoes and turnips. Using a mandolin (this is the easiest way), slice both vegetables 1/4 inch thick.
Place a layer of sweet potato slices on the bottom of a glass baking dish (9×9 or larger). Next, place a layer of turnip slices. Repeat until you use up all the veggies so you have layers of sweet potato then turnip.
In a medium saucepan, heat the coconut milk, water, and coconut butter (or maple syrup) over low heat until everything is liquid. Add in the lemon juice, herbs and spices, salt and mix to combine. Add in the starch 1/2 tbs. at a time, whisking continuously until the sauce thickens, should take about 3-5 minutes. You should have something slightly more watery than gravy but close to a gravy-like consistency.
Pour the sauce evenly over the vegetables and tip the baking dish from side to side to make sure the sauce seeps down between the layers.
Bake in the oven for about 45-50 minutes or until vegetables are fork tender. Keeps well in the fridge for up to 5 days.