Microwave Sweet Potato Gratin: Hassle-Free Yet Tasty

This microwave sweet potato gratin is as good as other similar recipes that use more ingredients and more complicated methods. Easy, quick, and delish…

A dish of sweet potato gratin cooked in a microwave.

Microwave Sweet Potato Gratin

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 flavorsome 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 cook the sweet potatoes partly instead of baking them in the oven. It’s an easy way to cut down cooking time so that you can get this side dish at about the same time as other dishes.

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 simultaneously, right?

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

You might wonder if cooking sweet potatoes in a microwave is bad. Just like anything, if we do it correctly, cooking in a microwave is safe and 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

The best thing about this recipe is that it is 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 flavor was surprisingly lovely. The cream complimented the sweet potatoes, and the duo tasted delicately creamy and delightful.

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

Again, you can choose any herb of your choice. 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 evenly over the sweet potatoes. You 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 with 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.

And if you want more ideas for a comfort casserole dish that tastes cheesy and tasty, you can try this Buffalo fries recipe.

Time and Energy-Saving 

As mentioned above, I love this way of making sweet potato gratin for its time- and energy-saving properties. Whenever I 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. 

Regarding energy, I must admit that some microwaves use a lot of power. However, nowadays, you can use energy efficiency-friendly microwaves like mine. 

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. 

But it usually takes me 10 minutes 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. 

A large oval dish for 5-6 people 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.

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

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

Storage Matter

Technically, you can freeze this sweet potato gratin once it’s completely cooled down. And it keeps well in the freezer for up to 8 weeks, provided 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. 

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

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

You can keep the gratin in the refrigerator for up to 4 days and reheat it when needed. 

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

Other Sweet Potato Recipes To Inspire You

Suppose you need more ideas for sweet potato recipes. In that case, you can try these oven baked sweet potato slices, pumpkin and sweet potato soup, Indonesian sweet potato slaw, or sweet potato balls in brown sugar coconut milk.

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.

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.

A dish of sweet potato gratin cooked in a microwave.
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4.93 from 13 votes

Microwave sweet potato gratin

A simplified sweet potato gratin that tastes as good as the original recipe with half of the effort and time.
Author: Devy Dar
Prep Time10 minutes
Cook Time20 minutes
Total Time30 minutes
Course: Lunch
Cuisine: International
Servings: 6


  • Chopping board
  • Kitchen knife
  • Casserole dish.


  • 2 pounds Sweet potatoes
  • 10.5 ounces Heavy cream/ Double cream
  • 2 tablespoons 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



  • Slice the sweet potatoes (you can use a mandolin cutter if you have) and arrange them in a greased dish. 
  • Sprinkle the salt and pepper over the sweet potatoes. 
  • Cut the butter in small chunks and scatter them over the potatoes. 
  • Sprinkle the chopped fresh herbs or dried herbs over the potato slices. 
  • 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). 
  • After 10 minutes, the potatoes are almost fully cooked. 
  • Then take the dish out and pour the cream over the sweet potatoes. It should cover ⅓ deep of the Gratin. 
  • Put the dish back in the microwave and cook further for about 7-10 minutes until the cream thickened and sweet potatoes thoroughly cooked.
  • 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 them. 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. 


Serving: 1g | Calories: 359kcal | Carbohydrates: 33g | Protein: 5g | Fat: 24g | Saturated Fat: 15g | Polyunsaturated Fat: 7g | Trans Fat: 1g | Cholesterol: 73mg | Sodium: 197mg | Fiber: 5g | Sugar: 11g


Nutritional info in this recipe is only estimate using online calculator. You should refer to it as a guide only. Please verify with your own data if you seek an accurate info.



Author: Devy Dar

Title: Food Writer, Recipe Developer, and Digital Content Creator.


Devy Dar founded So Yummy Recipes and Drizzling Flavor to share her love of food after exploring various cultures and cuisines for more than two decades. Her mission is to help others easily recreate traditional and non-traditional food with readily available ingredients. Her works have been featured in Reader’s Digest, Al Jazeera, MSN, Yahoo, Bon Appetit, and more. 

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  1. Giangi Townsend says:

    5 stars
    Soft, tender and packed with flavor, this recipe has become our favorite. Making it again this weekend by request.
    Thank you.

  2. 5 stars
    Sooo good! — and so easy! I used my mandolin to slice the sweet potatoes and was able to have this made for a side dish in less than 30 mins.

    1. Using mandolin to slice is the best. So you’ll know every slice will be cooked evenly at the same time.

  3. 5 stars
    Can’t beat this! This was way easier and faster than I ever dreamed. So scrumptious! The whole family loved it. 🙂

  4. 5 stars
    I never thought to microwave sweet potato gratin! This was easy and delicious. Good thing I googled, fast sweet potato gratin!

    1. Fast and save energy too ;-). I’m glad you like the gratin.

  5. 5 stars
    This sweet potato gratin saves your sanity when it comes to big meals! So much easier to whip up in the microwave than the traditional and just as delicious.

    1. Yup, we want easier cooking every time, don’t we? And this is one of them.

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