This gratin is pure sweet potato heaven. Thin layers of sliced sweet potatoes coated in cream and maple syrup bake up tender with a caramelized crust. While the slicing takes a bit of elbow grease, it's a simple process with only three ingredients. You can serve the gratin straight out of the pan. Or create a showstopper of a holiday side dish with individual portions and bruléed marshmallows.
When the weather is cold and the season is right, this maple-infused sweet potato gratin ends up on my client's tables often. And as eye-catching as the tender, stacked slices of bright sweet potatoes are, this gratin is truly quite simple. Even if you are a chronic skimmer of recipes, you will succeed wonderfully (you know who you are, and you're welcome).
And contrary to many sweet potato recipes labeled gratin or au gratin, this recipe does not call for cheese (I don't find the combination particularly appealing). Gratin in French means "to grate" or "with a crust". And adding cheese is not imperative. Just thinly-sliced, tender ingredients with a crispy top layer. Or marshmallows, if the holiday is right.
Three ingredients keep this particular potato gratin fairly affordable, approachable, and purely scrumptious.
- Sweet potatoes, any kind. When picking out sweet potatoes or yams at the market, look for wider ones. Any variety is delicious from red to jewel to garnet and the ever-trendy purple.
- Maple syrup. Buyer beware when hunting for maple syrup. Many are corn syrup with artificial colors and flavors. Look for the words "pure maple syrup" on the bottle. Or the prices that give you the most sticker shock. Pure maple syrup is not cheap, but you get more flavor bang for your buck. The grade of maple syrup doesn't matter for this recipe.
- Heavy cream. Heavy cream hydrates and enriches the sweet potatoes during baking. You can certainly use whole milk in a pinch. But since it's lower in fat milk will produce a slightly different result.
The beauty of this (no-recipe) recipe is that pan size and shape don't really matter. The key is to make sure you fill the pan right up to the top. Because the potatoes will cook down in the oven. So if you want to experiment with a larger batch or a different size or shape pan, this formula is a good starting point. Three pounds of sweet potatoes is about five or six average-size spuds.
Maple Cream Formula
For every three (3) pounds of potatoes:
1 cup heavy cream + ¼ cup maple syrup + 2 teaspoons of kosher salt
The key to a perfect gratin is to slice the potatoes thinly and about the same size. A mandolin is a helpful tool if you have one. But I often use my chef's knife. If you slice with a knife, first cut away one rounded side of the potato to create a flat, stable surface for cutting the rounds.
I typically bake sweet potato gratin in an eight or nine-inch nonstick cake pan. But you can use any similar-sized glass or ceramic dish you like. A springform pan is handy if you want to create individual portions with the baked gratin.
- Preheat and prep. Preheat the oven to 350° F. Coat your baking pan with cooking spray or butter it well. You can also line the bottom of the pan with a piece of parchment or wax paper. Especially if you plan to flip it out and cut individual servings, lining it makes the process much easier.
- Peel and slice the potatoes. Peel the sweet potatoes with a vegetable or y-shaped peeler, and trim the ends. Then with a mandolin or sharp knife, slice the potatoes about an eighth of an inch thick. No need to be exact, just aim for similar thickness among most of the slices.
- Ready the seasonings. Whisk together the heavy cream and maple syrup in a bowl or measuring cup with a spout. Measure out two teaspoons of salt into a small container.
- Shingle. Shingle the sweet potato slices into even layers in the baking pan. Sprinkle a little salt and drizzle a few tablespoons of the cream mixture on top of every other layer. By the time you place the last layer, you should have used all of the salt and cream mixture.
- Bake. Bake the gratin until a butter knife easily pierces all the way to the bottom, around an hour or a little more. If the top layer begins to brown too much before the potatoes are tender, cover it with foil. And if you'd like more browning, you can turn the broiler on once the potatoes are tender to crisp the top even more (watch it carefully, it only takes a couple of minutes).
You can serve the gratin out of the baking dish garnished with a dusting of cinnamon or dollops of plain yogurt or crème fraîche. Or cut and portion it for a special occasion (instructions below).
For Individual Servings
- Weight and cool. For a really beautiful presentation, press a piece of greased foil or parchment paper on top of the still-hot gratin. Then set a plate, slightly smaller pan, or removable tart/cake pan bottom on top that fits just inside the edges of the pan. Weigh the gratin down with a few canned goods or a similarly heavy item. Cool the gratin completely in the refrigerator (you can do this overnight).
- Loosen and flip. Run a butter knife around the outside of the gratin to loosen the potatoes from the edges of the pan. Place a plate, sheet pan, or cutting board on top of the pan. Then holding both tightly flip them over quickly to pop the gratin out of the pan. Repeat the process with a second cutting board to flip the gratin right-side up. Remove the parchment or foil you placed on top.
- Cut, warm, and garnish. With a cookie cutter or a knife, cut the gratin into your preferred shape. I like to use a pastry mold but a knife works just as well for creating squares or triangles. Place the individual portions on a greased or parchment-lined sheet pan and warm them in a 350° F oven until hot, about 10 to 15 minutes.
- Don't skimp on the salt. Since your only opportunity to season the potatoes is as you shingle them in the pan, season each layer evenly and well.
- Involve your handy helper. If you can't find a plate or pan that fits flat when you go to weigh down the baked gratin, find your family's craftsman or resident engineer. When I'm baking a layered potato dish that requires pressing, I have one of my boys cut out a piece of cardboard that fits just inside the top of the pan. I wrap it in foil and set it on top as a platform for the cans. The removable bottom of a same-size springform pan also works well.
- Brulée mini marshmallows. For a special holiday side dish, sprinkle a layer of mini marshmallows on top of the baked gratin. Then broil it on high heat until the marshmallows puff up and caramelize to a golden brown (watch it closely).
- Top the gratin with homemade marshmallow fluff. For an incredibly indulgent, stunning gratin whip up this homemade marshmallow fluff. It's an Italian meringue, which is not as tricky as it seems. And screams holiday cheer. You can add cinnamon, nutmeg, and the like, spread it on the gratin and brown it under the broiler. Or if you have a kitchen torch, you can brulée it tableside for dinner and a show!
Frequently Asked Questions
Depending on size, one sweet potato can weigh anywhere from five ounces to almost a pound. So it's best to weigh the potatoes on the scale at the grocery store to make sure you're buying the right amount for any recipe. A medium, average sweet potato weighs around 8 ounces.
Yes! Any and all potatoes are naturally gluten-free, sweet potatoes included. Certain prepared foods with sweet potatoes may not be gluten-free, so always read the ingredient labels. Many pre-cut, packaged sweet potato fries are coated in a seasoning that contains wheat flour or its derivatives.
- 3 pounds or 5 to 6 medium sweet potatoes, peeled
- ¼ cup of maple syrup (or honey)
- 1 cup of heavy whipping cream
- 2 teaspoons of kosher salt
- Preheat and prep. Preheat the oven to 350° F. Coat your baking pan with cooking spray or butter it well. You can also line the bottom of the pan with a piece of parchment or wax paper. Especially if you plan to flip it out and cut individual servings, the parchment makes the process much easier.
- Peel and slice the potatoes. Peel the sweet potatoes well with a vegetable or y-shaped peeler, and cut off any woody or pointed ends. Aim for slices ⅛"-thick. A mandolin is a helpful tool (but be careful!). A sharp chef's knife gets it done.
- Season the heavy cream. Whisk together the heavy cream and maple syrup in a small bowl or measuring glass. Measure the salt out in a small container.
- Layer the potatoes in the pan. Shingle the sweet potato slices across the bottom of your baking pan. Then drizzle a few tablespoons of the cream mixture and sprinkle a couple of pinches of the salt evenly over the layer. Repeat, making the layers as flat as possible and drizzling each with a little of the cream mixture and a sprinkling of salt. By the time you place the last layer, you should've used all the cream mixture and the entire two teaspoons of salt.
- Bake. Bake the gratin until a knife easily pierces all the way to the bottom, between 55 and 65 minutes. If the top layer begins to brown too much before the potatoes are tender, cover it with foil. If you want the top more browned and crispy, you can place the baked gratin under the broiler for a few minutes. Serve the gratin garnished with plain yogurt, crème fraîche, or a dusting of cinnamon or warm spices.
- Storage. Store any leftovers in the refrigerator for up to a week. Reheat the gratin in a 350° F oven until hot in the center.
For Individual Portions
- Weight and cool. Press a piece of greased foil or parchment paper on top of the still-hot gratin. Then set a plate, slightly smaller pan, or removable tart/cake pan bottom on top that fits just inside the edges of the pan. Set a few canned goods or a similarly heavy item on top. Cool the gratin completely in the refrigerator, overnight if you like.
- Loosen and flip. Run a butter knife around the outside of the gratin to loosen it from the edges of the pan. Place a plate, sheet pan, or cutting board on top of the pan. Then holding both tightly flip them over quickly to pop the gratin out. If the gratin doesn't immediately fall out of the baking dish, tap the bottom of the pan (or just give it a few moments). Place a cutting board upside-down on the freed gratin, and flip again to get it right-side up.
- Cut, warm, and serve. With a cookie cutter or a knife, cut the gratin into your preferred shape. I like to use a pastry mold or cookie cutter, but a knife works just as well for creating squares or triangles. Place the individual portions on a greased or parchment-lined sheet pan and warm them in a 350° F oven until hot, about 10 to 15 minutes.
On the maple syrup and salt. The amount of maple syrup in the recipe is subtle and lightly sweet. If you prefer a sweeter dish, add a few more tablespoons.
On the salt. The only chance you get to season the potatoes is before you bake the gratin. So season every single layer with salt as you build it. Two to three tablespoons of kosher salt is where I usually end up.
On slicing the potatoes. The key technique for a perfect gratin is to slice the potatoes thinly and about the same size. A mandolin is a helpful tool if you have one. But I often use my chef's knife. If you slice with a knife, first cut away one rounded side of the potato to create a flat, stable surface for cutting the rounds.
To add marshmallows. This is a delicious dish for the holidays and special occasions. To top the gratin with marshmallows first bake it completely. Then turn your broiler on high and spread a layer of marshmallows (I use mini) on top. Return the pan to the oven to brown the marshmallows. Watch it carefully to prevent burned marshmallows or a gratin on fire (true story, sadly).
- Prep Time: 25 minutes
- Cook Time: About 60 minutes
- Category: Side Dishes
- Method: Baking
- Cuisine: French
- Diet: Vegetarian
- Serving Size: 2-inch square portion
- Calories: 157
- Sugar: 8.2 g
- Sodium: 291.1 mg
- Fat: 8.6 g
- Carbohydrates: 19 g
- Fiber: 2 g
- Protein: 1.7 g
- Cholesterol: 26.9 mg
Keywords: sweet potato gratin, sweet potato gratin recipe, sweet potatoes with marshmallows
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