Sweet Potato Au Gratin with Blue Cheese

This delicious Sweet Potato Gratin recipe has just 5 ingredients: sliced sweet potatoes, creamy blue cheese, olive oil, cream, and pistachios for crunch!

With apologies to my mother and various other family members, I cannot stand mashed sweet potatoes with marshmallows on top. It’s such a pretty dish, with the marshmallow peaks toasted in the broiler, and I want to love it. But the sweet on sweet gets me every time. So imagine my delight when I came across a recipe in my Simplissime cookbook for a potimarron (a French winter squash) gratin baked with blue cheese. It inspired me to try a sweet potato take on this recipe. Et voilà! This Sweet Potato Au Gratin is the perfect mixture of sweet and savory, without a marshmallow in sight. Your holiday table may never be the same again.

The beauty of this recipe is the combination of the sweet sweet potato with salty, tangy blue cheese. Here in France, I chose a Fourme d’Ambert, which is a blue cheese made from cow’s milk. Its texture is soft and creamy, and it melts beautifully when baked. But any sharp creamy blue cheese will do just fine (you'll really taste the difference with a high-quality cheese). For some crunch, I’ve topped this with some chopped pistachios, though you could also use chopped pecans or almonds. 

How do you make Sweet Potato Au Gratin with Blue Cheese?

First, preheat your oven to 350 degrees Fahrenheit/175 degrees Celsuis. To prep ingredients, start by rinsing sweet potatoes, then patting dry. Poke several times with a fork on all sides. Place on a microwave-safe plate and microwave for 5-8 minutes until potatoes are just starting to soften, turning over once halfway through. They should not be completely tender at this point. Your microwave cook time will depend on how big your sweet potatoes are. Pre-cooking the sweet potatoes means they will not take as long to bake in the oven, and the cheese will not overcook.

When potatoes are cool enough, peel by starting to remove skin with a vegetable peeler or paring knife, then use your fingers to peel off. The skin should come off relatively easily. While potatoes are being microwaved, crumble around 6 ounces of best-quality, sharp blue cheese into small chunks. You will really taste the difference in this dish with a great blue cheese. Shell ½ cup of pistachios and chop roughly. To assemble, fill the bottom of an 8x8 baking dish or gratin dish with a layer of sweet potatoes, then sprinkle with blue cheese.

Repeat with the remaining sweet potato and blue cheese. Next, drizzle baking dish with 2 tablespoons heavy cream and 2 tablespoons olive oil. Sprinkle with salt and pepper.

Bake for 15-20 minutes, until cheese is melty and beginning to brown, and sweet potatoes can be pierced easily with the tip of a knife. Serve warm, garnished with chopped pistachios. 

You can also make this dish in adorable individual serving sizes like these in mini cocottes. You could easily use ramekins as well. Just keep in mind that you may need to slice your sweet potatoes in smaller pieces in order to fit.

What does au gratin mean? 

Au gratin, or gratin, is the term for a French culinary technique in which something is baked in a shallow dish under high heat so that its topping (cheese, egg, breadcrumbs, butter) becomes a golden brown crust. All kinds of vegetable, meat, and seafood au gratin dishes exist, though potatoes au gratin is perhaps the most classic. This dish is also known as scalloped potatoes. For a different take on a traditional gratin, don't miss my White Asparagus Roquefort Gratin.

What is the difference between a potato gratin and dauphinoise?

The difference between potato gratin and dauphinoise comes down to cheese. In a gratin recipe, potatoes are cooked with both cream and cheese. Dauphinoise recipes traditionally only include cream. 

Can I make this Sweet Potato Gratin ahead of time? 

Yes, you can make this dish up to 24 hours in advance. Prep all your ingredients, put them together in your baking dish, and cover them tightly with plastic wrap. (Keep chopped pistachios separately in a small container at room temperature.) Refrigerate, and bring back to room temperature before baking.  

What pairs well with sweet potato gratin? 

Sweet potato au gratin is a great side dish for any kind of roast meat: turkey of course, but also rotisserie chicken, pork chops, or a baked ham. Or how about pairing with my Pan-Seared Filet Mignon with Red Wine Sauce? This recipe would go well with my Panko Crusted Salmon Fillets or with my Foil Packet Tilapia with Zucchini, Lemon, and Butter.

And, this is such a hearty dish that you could easily go vegetarian and just pair it with a big salad like my Kale Salad with Cranberries or Spinach Beet Salad with Goat Cheese. Or serve with another delicious fall/winter vegetable like these Balsamic Glazed Brussels Sprouts.