Microwave Sweet Potato Gratin: Hassle-Free Yet Tasty

A dish of sweet potato gratin cooked in a microwave.

 Microwave Sweet Potato Gratin

This microwave sweet potato gratin is as good as the old-fashioned gratin made in an oven. Even better, this one will save you a whale of time to cook. Therefore, this recipe is a perfect choice when you have many other dishes to prepare for your food spread. 

Traditional Sunday roast, family gathering, holiday or festive season can be one of those occasions when you need this flavoursome sweet potato gratin.

Microwave sweet potato gratin in a rectangle dish.

And it pairs so well with meaty dishes, such as roast lamb or chicken. And of course, with plenty of veggie trimmings, i.e. roasted parsnips, green beans, Brussels sprouts, etc. In other words, with all those lovely roast menus. 

As the name implies, this creamy gratin uses a microwave to partly cook the sweet potatoes instead of baking them in the oven. It’s an easy way to cut down cooking time so you can get this side dish about the same time as other dishes.

Let’s admit, when you do a full roasties spread, you’ll need lots of space in the oven. But not everyone has a large enough oven to cook many dishes at the same time, right?

So yeah, if you have that problem (just like I do), this gratin made in the microwave can be your saviour.

You might wonder if it is bad to cook sweet potatoes in a microwave. Just like anything, if we do it correctly, cooking in a microwave is safe, harmless and does not destroy the nutrients in the food. I like the article from BBC on “Is it safe to microwave food?”. You can take a look at it here

Simple And Forgiving Ingredients

Now, the best thing about this recipe is that it is really forgiving and flexible. You can alter and adjust according to your mood and your liking. Sweet, isn’t it?

So you only need 2 main ingredients. They are sweet potatoes and cream. Ideally, you choose heavy cream/ double cream, but you can also use single cream.

I have made it in the past with only these two ingredients, and I was happy as the flavour was surprisingly lovely. The cream simply complimented the sweet potatoes that the duo tasted delicately creamy and delightful.

However, to elevate the flavour, I suggest adding herbs and hard cheese to make the dish even more delicious. 

Again, you can choose any herb of your choice. Though in my humble opinion, sage or rosemary are the most delicious options. You may use fresh herbs or dried herbs. Chop the fresh herbs finely and scatter them around evenly over the sweet potatoes. You will only need a little, as you don’t want an overpowering aroma. 

You only need about 1 teaspoon of chopped fresh herbs of your choice. But make sure you go easy with dried ones, as they have a more intense fragrance. I would put ¼ teaspoon of dried herbs. 

As for the cheese, hard cheese is the best option. I quite like this Italian style hard cheese.

Time and energy saving 

As mentioned above, I love this way of making sweet potato gratin for its time and energy saving. Because whenever I do roast and want to have this gratin, I don’t have enough space in the oven. 

And really, to make this gratin in the oven will take me at least an hour. So, the microwave helped me cut it down to only 17-20 minutes. 

When it comes to energy, I must admit that some microwaves use a lot of power. However, nowadays you can use energy efficiency friendly microwaves like this one I have. 

How long does it take to cook a sweet potato in a microwave? 

It shouldn’t take longer than to cook white potatoes. 

The first time I tried to make this gratin in the microwave, I wasn’t sure how long I should cook the sweet potato in it. 

But it usually takes 10 minutes for me to make a medium-sized jacket potato (with white potato). So I based that timing on sweet potato. 

To make the gratin, I microwave sweet potatoes twice. First, I microwave them with butter, salt and pepper for 10 minutes. 

And the second time, I microwave them with heavy cream/ double cream and cheese (when using) for about 7 minutes. 

After the first cooking time, the sweet potatoes were actually cooked. The second cooking time is more for the cream to get absorbed by the softened sweet potatoes. 


This recipe is very easy and simple, and also it’s quite cheap and cheerful. 

For a large oval dish enough for 5-6 people, it only costs me less than a fiver. At the time of writing, I only spent about $3 on this gratin. Plus another $2 if I use hard cheese.

The reason it is fairly cheap is that I only have to buy two main ingredients. Sweet potatoes and double cream. The rest of the ingredients are just things I always have in my kitchen. 

A close up of sweet potato gratin that was cooked in microwave.

Storage Matter

Technically, you can always freeze this sweet potato gratin once it’s completely cooled down. And it keeps well in the freezer for up to 8 weeks providing you put it in a freezer friendly food container.

Take it out of the freezer and leave it in the refrigerator overnight the day before serving. So it thaws properly. 

You can reheat the gratin in the microwave for about 2-3 minutes, depending on the size. Or, you can reheat it in the oven or air fryer. The latter will take less time. 

As a basic rule, once it has fully thawed you should not refreeze it.  

And you can keep the gratin in the refrigerator for up to 4 days and reheat it when you need it. 

I recommend you leave the dish out of the fridge to come to room temperature before you reheat it. 

Other recipes to inspire you

Thank you for stopping by this microwave sweet potato gratin recipe. I hope you’ll try it. When you do, it will be great if you can share what you think about it in the comments below.

Take a look at my comfort dessert recipes that go along with this gratin that you may like.

And please follow me on Facebook, Instagram and/or Pinterest. To sneak a peek at what’s cooking in my kitchen. 

Take care and all the best.

Yield: 6

Microwave sweet potato gratin

A dish of sweet potato gratin cooked in a microwave.

A simplified sweet potato gratin that tastes as good as the original recipe with half of the effort and time.

Prep Time 10 minutes
Cook Time 20 minutes
Total Time 30 minutes


  • 2 lbs/ 900 gr Sweet potatoes
  • 10.5 oz/ 300 ml Heavy cream/ Double cream
  • 2 tbsp of butter and more to grease the dish
  • Salt to taste
  • Freshly ground black pepper
  • Generous handful of grated hard cheese.
  • Herbs of your choice


  1. Slice the sweet potatoes (you can use a mandolin cutter if you have) and arrange them in a greased dish. 
  2. Sprinkle the salt and pepper over the sweet potatoes. 
  3. Cut the butter in small chunks and scatter them over the potatoes. 
  4. Sprinkle the chopped fresh herbs or dried herbs over the potato slices. 
  5. Put the dish in the microwave and cover it with a microwave plate cover. Cook the potatoes for 10 minutes at high (180° C/ 356° F). 
  6. After 10 minutes, the potatoes are almost fully cooked. 
  7. Then take the dish out and pour the cream over the sweet potatoes. It should cover ⅓ deep of the Gratin. 
  8. Put the dish back in the microwave and cook further for about 7-10 minutes until the cream thickened and sweet potatoes thoroughly cooked.
  9. Enjoy. 


  • Try to slice the potatoes at the same thickness. I normally aim to cut in 0.08 in/ 2 mm thick. 
  • When it comes to cooking, it's best to experiment with the ingredients according to your taste ?. Things like herbs can be experimental and personal. So, choose the herbs that you like or don't use herbs at all if you don't like it. Just challenge your own taste bud and use the recipe as your guidance. 
  • As I explained above, this microwave sweet potato Gratin is nice as a side dish for your roast menu. But it's delicious to eat it on its own. 

Nutrition Information



Serving Size


Amount Per Serving Calories 359Total Fat 24gSaturated Fat 15gTrans Fat 1gUnsaturated Fat 7gCholesterol 73mgSodium 197mgCarbohydrates 33gFiber 5gSugar 11gProtein 5g

The nutrition calculation you find here is just a guide provided by online nutrition calculator. You should not use to substitute advice from nutritionists or health practitioners.

Did you try the recipe?

Share how you like the recipe in the comments below and show a picture of your creation



Leave a Reply

Your email address will not be published.