How to Make Sweet Potato au Gratin
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INGREDIENTS
- 2 medium sweet potatoes, peeled and thinly sliced
- 4 gold potatoes, peeled and thinly sliced
Sauce:
- 2 cups/500 milliliters cooking cream
- 3 cloves garlic, pressed
- 2 teaspoons salt
- ¼ teaspoon ground nutmeg
- ¼ teaspoon white pepper
Topping:
- Fresh thyme leaves
- Grana Padano, Parmesan, and/or Kashkaval cheese, grated
INSTRUCTIONS
- Preheat the oven to 355F (180C).
- Whisk all the sauce ingredients in a bowl.
- Arrange the potato and sweet potato slices tightly in a spiral pattern inside a round 12” (32cm) baking dish. Pour over the sauce, sprinkle thyme and cheese and bake for about 30 minutes or until the potatoes are tender.
MY NOTES
FAQ
Can I substitute the cooking cream with a lighter option?
Yes, you can substitute cooking cream with lighter options in this sweet potato au gratin recipe. Half-and-half or whole milk can be used for a lighter version, though the dish may be less creamy. For an even lower-fat option, try using evaporated milk or a mixture of milk and Greek yogurt. Keep in mind that these substitutes may slightly alter the texture and richness of the gratin, but they can still provide a delicious result.
What type of potatoes work best for this gratin?
For the best results in this sweet potato au gratin recipe, choose starchy potatoes like Russet or Yukon Gold. Russet potatoes have a high starch content, which helps them break down and create a creamy, tender texture. Yukon Gold potatoes are slightly waxy with a buttery flavor, providing a balance between creaminess and structure. Avoid using waxy potatoes like red or fingerling varieties, as they hold their shape too well and won’t create the desired soft, layered consistency.
Can I make this dish ahead of time and reheat it?
Yes, you can make this sweet potato au gratin ahead of time and reheat it later. Prepare the dish as usual, bake it, and allow it to cool completely before covering it tightly with foil or plastic wrap. Store it in the refrigerator for up to two days. When you’re ready to serve, reheat the gratin in the oven at 350°F (175°C) for 20-30 minutes, or until it’s warmed through and the top is slightly crispy. Reheating may cause the dish to dry out a bit, so you can add a small amount of cream or milk before reheating if needed.
How do I prevent the gratin from becoming too watery?
To prevent your sweet potato au gratin from becoming too watery, start by slicing the potatoes evenly so they cook consistently. Use starchy potatoes like Russet or Yukon Gold, which release less water during baking. Make sure to drain any excess liquid from the potatoes before layering them. Avoid covering the dish while baking, as this traps steam and adds moisture. If your gratin still seems watery, allow it to rest for 10-15 minutes after baking to set and thicken.
Is it possible to add other vegetables to this recipe?
Yes, you can add other vegetables to this sweet potato au gratin recipe for extra flavor and texture. Popular choices include thinly sliced carrots, parsnips, or zucchini, which blend well with the potatoes. You can also layer in sautéed spinach, leeks, or mushrooms for added depth. When adding vegetables, slice them thinly so they cook evenly with the potatoes. Keep in mind that some vegetables, like zucchini, may release more moisture, so consider reducing the cream slightly or pre-cooking them to avoid a watery gratin. Experimenting with different vegetables can create a unique and delicious variation of the dish.
What can I use as a substitute for Grana Padano or Parmesan cheese?
If you’re looking for a substitute for Grana Padano or Parmesan cheese in your sweet potato au gratin, several options can work well. Pecorino Romano is a great alternative, offering a sharper and saltier flavor that pairs nicely with the dish. Asiago cheese is another good option, providing a nutty and slightly sweet taste. For a milder choice, try Gruyère, which melts beautifully and adds a rich, creamy texture. If you need a dairy-free substitute, nutritional yeast offers a cheesy flavor without the dairy. Each of these alternatives can enhance your gratin with a unique taste and texture.
What can I use as a substitute for Grana Padano or Parmesan cheese?
If you’re looking for a substitute for Grana Padano or Parmesan cheese in your sweet potato au gratin, several options can work well. Pecorino Romano is a great alternative, offering a sharper and saltier flavor that pairs nicely with the dish. Asiago cheese is another good option, providing a nutty and slightly sweet taste. For a milder choice, try Gruyère, which melts beautifully and adds a rich, creamy texture. If you need a dairy-free substitute, nutritional yeast offers a cheesy flavor without the dairy. Each of these alternatives can enhance your gratin with a unique taste and texture.
How can I ensure that the sweet potatoes and potatoes cook evenly?
To ensure sweet potatoes and potatoes cook evenly in your gratin, slice them uniformly using a mandoline or a sharp knife. Aim for slices about 1/8-inch thick. Arrange the slices in even, overlapping layers to promote consistent cooking. Pre-cooking the slices in boiling water for a few minutes can also help them cook more uniformly in the oven. Bake the gratin at a moderate temperature, around 350°F (175°C), to allow the potatoes to cook through without burning the top.
Should I cover the gratin with foil while baking?
You generally do not need to cover the gratin with foil while baking, as this can prevent the top from becoming crispy. However, if you notice the top is browning too quickly, you can loosely cover it with foil to prevent burning while the inside continues to cook. For even cooking, start baking uncovered and only cover with foil towards the end of the baking time if needed to protect the top from over-browning.
Can I make this recipe dairy-free?
Yes, you can make this sweet potato au gratin dairy-free by using plant-based alternatives for the cream and cheese. Substitute the cooking cream with unsweetened almond milk, coconut milk, or oat milk combined with a bit of dairy-free thickener like cornstarch or arrowroot powder. For the cheese, use vegan cheese shreds or nutritional yeast, which provides a cheesy flavor without dairy. Ensure the vegan cheese melts well to achieve a creamy texture. Adjust seasoning as needed, since dairy-free substitutes might have different flavor profiles. This way, you can enjoy a delicious dairy-free version of the gratin.
