For years, it’s been a Thanksgiving (and Christmas!) tradition that I make a Gratin Dauphinoise for the Chief Taste Tester over here at Meatified HQ. The first year I made it, he had no idea what it was. His eyes practically rolled back in his head at first taste and every subsequent year he’d beg me to make a bigger pan so there would be leftovers. Then, we went Paleo. And not only were potatoes out, but so was the cream. Uh oh. Thus came the inevitable request for a Paleo Sweet Potato Gratin. No pressure.
So I set about trying to come up with something which could take the carb and starch-fest’s place on the table at special occasions. At first I thought this would be easy: yay sweet potatoes! Yay coconut milk! Until I, of course, realized that coconut milk really doesn’t thicken too much on its own. I thought about using some arrowroot as an extra thickener, but that stuff is a pain in the butt due to the fact that it’s really not stable if you get it too hot. That wasn’t going to work in an oven dish.
So then I did some research and realized that heavy cream thickens because it has such a high fat content. Much higher, in fact, than coconut milk. So smartypants me thinks, “Easy! Add fats!”. This did – kind of – work. Aside from the fact that I added far too much coconut oil. While it was a pretty promising attempt, not only was it not thick or “creamy” enough, there was a really grody layer of sweet-potato-orange fat on the bottom of the dish. Not exactly appealing. So still no Paleo Sweet Potato Gratin.
Then I recalled how pumpkin had helped me make an awesome paleo risotto not too long ago and I realized that would help round out the sauce and give more substance to the layers between the sweet potatoes. Genius! Now I just have to remind the Chief Taste Tester that he’s not getting this Paleo Sweet Potato Gratin every weekend!
How to make a Paleo Sweet Potato Gratin, step by step!
Slice sweet potatoes to approximately 1/8th inch thick. Unless you have the patience of a saint, use a mandoline or the slicer on a food processor. I think I’d lose some digits if I tried to do this by hand.
Thinly slice the shallot, too and set aside while you grease a 7×11 baking dish with oil of your choice (or you can make individual ramekins, as pictured). You can use a slightly larger dish if you need to, but this one works really well to get enough depth to the gratin. If you make it in a larger dish, you’ll have fewer layers so you’ll need to reduce the cooking time later. Place an overlapping layer of sweet potato slices on the bottom of the dish; alternate with sliced shallots.
Continue until all sweet potato and shallot slices are used up: this should make 4 layers of sweet potato (& 3 of shallots). Save the larger slices for the final layer.
Preheat oven to 400F while you make the sauce. Add the coconut butter to a saucepan over very low heat (mine was 1/10); when melted, add the almond flour. You’re basically making a paleo / starch free white sauce here.
Add the coconut milk in half cup increments, whisking each time to combine. There will be a few lumps which is fine!
Now you should have something which looks like a thin cream sauce. Too thin, actually.
Now it looks more pretty, but it’s still too thin.
Here’s where the magic happens! Add the pumpkin puree and whisk until smooth.
Yay, your sauce is much thicker now! In fact, it’s just a tad thicker than cream would be, which is perfect. Turn up the heat to a low-medium and heat for a few minutes until sauce is warm and pourable.
Pour the sauce over the gratin dish, making sure the top is evenly covered, but leaving a little gap between the top of the potatoes and the lip of the dish or dishes. That way they won’t overflow! If you are using individual ramekins, put them on a baking tray before cooking.
Bake the sweet potato gratin in the oven for 30 – 40 minutes, uncovered, until the potatoes are cooked through and the top is brown. If you let this rest for 5 – 10 minutes when it comes out of the oven, it should slice perfectly!
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