When the weather turns chilly, there's nothing more comforting than the smell of roasted sweet potato. In Korea, vendors sell these on the street all winter long. The skin chars slightly, the inside turns sticky and sweet, and you eat it hot, peeling back the skin with your fingers.
This is the air fryer version. Same caramelized result, no outdoor fire pit required.
Why I Love This Recipe
This is probably the most minimal recipe I have ever published. One ingredient. One appliance. No prep. And yet every time I make these, they feel like a treat.
I grew up seeing Korean sweet potato vendors on TV and in movies, that iconic metal drum with coals and sweet potatoes piled on top in a heap. The vendor would pick one up with tongs, weigh it, and hand it to you in a paper bag. You'd eat it standing on the sidewalk, blowing on each bite because it was too hot to wait. The inside would be dense and sticky and almost caramel-like in a way that no other preparation can replicate.
The air fryer gets surprisingly close to that. What I appreciate most is that you genuinely cannot mess this up. There is no sauce to balance, no seasoning to add, no technique to perfect. The sweet potato does all the work. The only real question is timing, and once you have made these once, you will know exactly what to look for.
What Is Korean Sweet Potato (군고구마)?
군고구마 (gungoguma) means roasted sweet potato in Korean. What makes it different from the orange sweet potatoes you might know is the variety itself. Korean sweet potatoes have pale yellow flesh, a denser and starchier texture, and a subtly sweet, almost nutty flavor. When roasted, the natural sugars caramelize and the inside becomes rich and creamy without going mushy.
The American orange sweet potato is much softer and moister when cooked. It falls apart. Korean sweet potatoes hold their shape and get that sticky, dense interior that's the whole point of gungoguma.
The difference between the two is significant enough that I would not substitute one for the other in this recipe. The orange variety simply will not develop the same texture no matter how long you cook it. If gungoguma is what you are after, seek out the Korean variety.
How to Pick the Right One
Look for smaller to medium-sized sweet potatoes. They roast more evenly and tend to be sweeter. The skin should be smooth and unblemished with no soft spots or cracks. Pick one up and it should feel heavy for its size.
The variety to look for is Bam-goguma (chestnut sweet potato). It has a denser texture that caramelizes beautifully. You can usually find Korean sweet potatoes at H Mart or any Korean grocery store.
I have also found them at some Asian grocery stores that carry Korean produce. They are sometimes labeled simply as "Korean sweet potato" or "Asian sweet potato" with pale, reddish-purple skin and a visibly different look from the standard orange or garnet sweet potato. If you are unsure, just ask someone at the store.
Avoid any that feel soft when pressed, have green patches near the skin, or look like they have been sitting out for a long time. A fresh one will feel firm and dense from tip to tip.
The Ingredients 🛒
Servings
Tap to scale
- Korean sweet potatoes: 2 medium (about 200g each)
- Optional: pinch of sea salt or drizzle of honey for serving
Step-by-Step 🍠
1. Wash and Dry
Wash and scrub the sweet potatoes well under running water. Pat them completely dry. No need to peel or cut.
2. Load the Air Fryer
Place whole sweet potatoes in the air fryer basket. Don't stack them. If you have more, cook in batches so the heat circulates evenly.
3. Air Fryer
Set the air fryer to 375°F (190°C). Cook for 35 to 45 minutes depending on size. Flip them halfway through.
4. Check Doneness
Pierce with a fork or chopstick. It should slide in easily with no resistance. The skin will look slightly blistered and the sweet potato should feel soft all the way through.
5. Serve
Let cool for a few minutes so you don't burn your fingers. Peel back the skin and eat as-is, or add a pinch of sea salt or a drizzle of honey. That's it.
Tips
Size matters. Smaller sweet potatoes cook faster and more evenly. Very large ones may need the full 45 minutes or slightly longer.
Don't rush it. The long cook time is what allows the sugars to fully caramelize. If you pull them too early, the inside won't have that sticky, jammy texture.
Check your air fryer. Every air fryer runs slightly differently. Start checking at 35 minutes and go from there.
The skin blisters: Do not be alarmed when the skin starts to look wrinkled and slightly blistered toward the end. That is exactly what you want. Some natural sugars will even seep out through small cracks in the skin and caramelize on the surface. Those little sticky spots are the best part.
Preheating: I recommend preheating your air fryer for 3 to 5 minutes before adding the sweet potatoes. Starting in a fully hot environment jumpstarts the caramelization process and gives you a better result on the skin.
Tips & Notes
Can I use a regular oven? Yes. Place the sweet potatoes directly on the oven rack or on a lined baking sheet at 400°F (205°C) for 45 to 60 minutes, flipping once halfway through. The result is slightly less concentrated than the air fryer version but still delicious.
Can I wrap them in foil? I would skip the foil. Wrapping in foil steams the potato rather than roasting it, which softens the texture but prevents the skin from blistering and the inside from getting that dense, caramelized quality. Leave them bare in the basket.
Serving ideas: Beyond salt and honey, a thin spread of good butter on the cut surface is incredible. A sprinkle of cinnamon is another option if you want a warmer, spiced flavor. Some people also eat gungoguma with a side of kimchi, which sounds unusual but the acidic, fermented flavor contrasts beautifully with the sweetness.
Storage: These keep well in the fridge for up to three days. Reheat in the air fryer at 350°F for about 8 to 10 minutes and they come back almost as good as fresh. I would not microwave them since the texture turns a little dense and dry.
Meal prep: If you want a week's worth of easy snacks, roast four to six at once in batches and refrigerate them. They make a genuinely satisfying afternoon snack that feels indulgent but is nothing more than a sweet potato.
Serving Suggestions
The simplest way to eat this is right out of the air fryer, peeled and eaten as-is. That is the authentic street food experience and honestly the best one.
If you want to dress it up slightly, slice it down the middle lengthwise, fluff the interior with a fork, and add a small pat of salted butter. The butter melts into the warm, sticky flesh and gives it a slightly richer, rounder flavor.
For a light dessert, drizzle honey over the exposed flesh and add a tiny pinch of flaky sea salt. The sweet and salty contrast against the naturally sweet potato is a genuinely good combination.
The Verdict
There is something about the smell of these things cooking that makes it impossible to wait. Vincent ate his straight out of the air fryer, just peeled the skin back and went. No honey, no salt. Just the sweet potato.
If you find Korean sweet potatoes at your local H Mart, grab a bag. This is the easiest recipe on the site and one of the most satisfying.
