Korean Candied Sweet Potatoes (Goguma Mattang)

Name: Korean Candied Sweet Potatoes (Goguma Mattang)
Prep time: 7 min
Cook time: 15 min
Total time: 22 min
Ingredients: 1 lb Korean or Japanese sweet potatoes ( - about two medium sweet potatoes); ½ cup sugar; 3 Tablespoons cooking oil ( - plus extra for deep frying); 1 Tablespoon toasted black sesame seeds; pinch of salt

Jump to Recipe

Korean candied sweet potatoes (goguma mattang) are fried pieces of sweet potatoes covered in a hard candy shell made of caramelized sugar!

Korean candied sweet potatoes with golden caramel coating and black sesame seeds on a white plate

Korean candied sweet potatoes, called goguma mattang (고구마 맛탕), is made from deep fried pieces of Korean sweet potato that's candied with a golden brown, hard candy shell!

The hard, caramelized candy coating gives these Korean candied sweet potatoes a beautiful sheen and caramel color that's makes this the perfect sweet potato dessert for fall or winter!

hand holding Korean caramelized sweet potato showing fluffy inside with hard candy shell

This is very similar to Japanese candied sweet potatoes, also called Daigaku Imo. The Korean version (Goguma Mattang) has a slightly thicker and hard caramelized coating that has a wonderful crunchy texture - almost like brittle.

Caramelized sweet potatoes are a simple, delicious Thanksgiving snack or dessert that's easy to make and loved by all - children and adults!

close up of Japanese candied sweet potatoes with caramelized coating and black sesame seeds

Why this recipe works

Deep frying the sweet potatoes make them tender and soft on the inside with a crispy outer layer.
Coating these fried sweet potato pieces with a hard candy shell adds an amazing crunchy texture made of caramelized sugar!
The hard candy coating keeps the sweet potatoes soft and fluffy on the inside and adds an amazing contrast in texture!
If you prefer the caramel candy to have a deep, darker color with a slight hint of bitterness, let the caramel cook for a bit longer but keep a close eye on it. I find a subtle hint of bitterness adds depth of flavor and prevents it from tasting too sweet.
Be careful not to cook the caramel too long as it can burn very quickly. Too much bitterness is an indication that it cooked for too long and burned.

Korean candied sweet potatoes, goguma mattang, covered in golden brown caramel candy and sprinkled with black sesame seeds

Ingredients you'll need

labeled ingredients for Korean candied sweet potatoes in small white bowls

Korean sweet potatoes - also called Japanese sweet potatoes. These have a purplish red skin and pale yellow interior. They also have less moisture than American sweet potatoes and are more similar in texture to chestnuts. They're very sweet and tender when cooked.
Sugar - Use plain white sugar for this recipe since we're making a hard, caramel candy.

Step by step instructions

numbered step by step photos for making Korean candied sweet potatoes

Wash and dry the sweet potatoes thoroughly. Any remaining moisture on the sweet potatoes will cause splatter when fried.
Cut the sweet potato into bite sized wedges. I like to cut them at an angle and then rotate the sweet potato for different shapes.
Deep fry the sweet potato pieces at 340 degrees F for about 6 to 8 minutes or until they are golden brown and tender. Insert a toothpick to check for doneness. If your pieces are smaller, reduce the frying time.

golden brown fried sweet potato pieces on a paper towel

Make the caramel candy - Add the oil and sugar into a shallow pan and heat over low heat. Once the sugar starts to melt, slowly swirl the pan and allow the caramel to turn a golden brown color. Once it starts to bubble up on itself and foam, add the fried sweet potato pieces.
Toss the sweet potato pieces with the caramel candy until each piece is coated.
Lay them separately on parchment paper. Quickly sprinkle on black sesame seeds before the candy hardens. Serve when the candy coating hardens.

Korean caramelized sweet potatoes garnished with black sesame seeds

Frequently Asked Questions

close up of Japanese candied sweet potato, Daigaku Imo

What are Korean sweet potatos?

Korean sweet potatoes, also called Japanese sweet potatoes or Asian sweet potatoes, have a red purplish skin with a pale, yellow interior. They're very sweet and have a soft, fluffy texture when cooked and will turn a golden yellow color inside.

They're different from American sweet potatoes because they have less moisture and a texture more similar to roasted chestnuts.

Where can I buy Korean or Japanese sweet potatoes?

You can buy them in any Asian grocery store, including Korean, Japanese, and Chinese markets.

Can you eat the skin of the sweet potato?

Yes the skin is safe to eat! Make sure to scrub the skin well and wash under running water. The skin contains fiber and and nutrients so keep the peel on if you prefer to.

How do I store leftovers?

These are best when consumed right away. The hard candy shell will start to soften if left out for too long.

You can refrigerate any leftovers in an airtight container but the hard caramel coating will turn into a sweet syrup, which is still delicious but different from the crunchy candy coating it had when first made.

Want more? Try these other recipes: