Korean Roasted Sweet Potato

Quick answer

Total time: 45 min
Level: Easy
Servings: 2 servings
Ingredients: 6

About this dish

Gun-goguma is a Korean winter snack made by roasting whole sweet potatoes in their skins at 200 degrees Celsius for 35 to 40 minutes.

The slow heat converts the starches inside the potato into maltose, concentrating the sweetness and producing a sticky, honey-like layer just beneath the skin. Lower-temperature roasting is preferred over high heat because it extends the window of enzyme activity, allowing sugars to accumulate gradually rather than burning off at the surface. Korean pumpkin sweet potatoes, called hobak-goguma, have a higher moisture content and more pronounced natural sweetness, so they turn creamy and almost runny when fully roasted. Resting the potatoes at room temperature for a day or two before roasting further boosts sugar levels, since starch conversion continues during storage. The potato is satisfying on its own, but adding a pat of butter or a dusting of cinnamon layers in a rich, aromatic contrast. Eating the skin along with the flesh adds fiber and a slightly earthy counterpoint to the pure sweetness of the interior.

Ingredients

servings

IngredientAmountUnit

sweet potatoes4 eaea

coarse salt1 tsptsp

water50 mlml

butter1 tbsptbsp

honey1 tbsptbsp

cinnamon powder½ tsptsp

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Instructions

Read the steps as a cooking flow: prep, heat, seasoning, doneness control, and finish.

6 steps

1

Step

Scrub the 4 sweet potatoes with a brush until no soil remains, then dry the skins well.

If any are much larger, halve them lengthwise so every piece roasts at a similar pace.
2

Season

Spread 1 teaspoon coarse salt in a thin, even layer on the oven tray.

Set the sweet potatoes on the salt so the bottoms are buffered from direct heat and do not scorch.
3

Control

Preheat the oven fully to 200°C before adding the tray.

Place 50 ml water at one side of the tray or in a small oven-safe dish to reduce drying around the skins.
4

Step

Roast for 35 to 40 minutes.

At about 20 minutes, turn each piece over; the skins should start to wrinkle lightly, and a sweet roasted smell should develop without blackening.
5

Prep

Test the thickest part with a chopstick.

If it slides in without resistance, remove the tray; if the center still feels firm, roast 5 minutes longer and check again.
6

Finish

Let the sweet potatoes rest for 5 minutes so the steam settles inside.

While still hot, split them open, add the butter, honey, and cinnamon powder, and serve before the butter cools.

Practical Cooking Checks

The cues that matter most while cooking.

Key technique: Gun-goguma concentrates natural sugars through slow roasting to create a soft, honey-like center.
Finish cue: Let the sweet potatoes rest for 5 minutes so the steam settles inside.
Avoid this: Set the sweet potatoes on the salt so the bottoms are buffered from direct heat and do not scorch.
Storage and reheating: Resting the potatoes at room temperature for a day or two before roasting further boosts sugar levels, since starch conversion continues during storage.