Ben Yagi's Sweet Potato Recipe: Smoky Cinnamon Crunch with Charred Edges

Ben Yagi's sweet potato recipe transforms humble sweet potatoes into a delicate dessert with smoky charred edges and a warm cinnamon crunch—just like the legendary Japanese wagashi master. This traditional technique requires patience and precision, but the result is a dish that balances earthy sweetness with subtle complexity. The key lies in slow-roasting the sweet potatoes until their edges develop a beautiful caramelized crust, then pairing them with rich red bean paste for a perfect harmony of textures.

What sets this recipe apart is the attention to traditional methods—steaming the sweet potatoes first to soften them gently, then finishing them on a hot griddle to achieve those coveted charred edges.

The smoky aroma alone makes the kitchen feel like a Japanese patisserie, while the cinnamon sprinkle adds warmth that complements the natural sweetness of the potatoes. This dish isn't just about taste; it's about the experience of creating something that feels both rustic and refined.

The final assembly brings everything together: tender sweet potatoes with their crispy edges, a generous dollop of smooth red bean paste, and a light dusting of cinnamon.

The contrast between the soft interior and the caramelized exterior creates a satisfying bite, while the bean paste adds a creamy, slightly sweet element that ties the dish together. It's the kind of dessert that feels special enough for guests but simple enough to make at home.

Perfect for autumn gatherings or as a thoughtful homemade gift, this recipe captures the essence of Japanese wagashi—elegant, balanced, and deeply satisfying. The technique may seem precise, but once you master it, you'll find yourself reaching for sweet potatoes time and time again.

Let's bring Ben Yagi's tradition to your kitchen.

Ingredients for ben yagi sweet potato

Transform humble sweet potatoes into elegant wagashi with these traditional Japanese ingredients.

The sweet potatoes are the foundation—Jewel variety works best for its natural sweetness and smooth texture. Japanese markets often carry them pre-peeled and ready to use, but if you're buying from a regular grocery store, look for firm, unblemished potatoes about the size of a tennis ball. The red bean paste should be smooth and vibrant—Koyoan brand is a reliable choice, but any high-quality anko will work. For the cinnamon, Ceylon has a more delicate flavor than cassia, which can be slightly bitter. If you can't find Ceylon, use regular ground cinnamon but reduce to 1.5 tbsp to avoid overpowering the dish.

No red bean paste on hand? Sweetened mashed beans (like cannellini beans blended with sugar) can work in a pinch, though the texture won't be identical. Want to skip the honey drizzle? A light dusting of powdered sugar adds sweetness without altering the dish's rustic charm. The sesame seeds can be swapped for toasted pine nuts if you prefer a different crunch. For the butter, European-style unsalted (like Plugrá) melts more smoothly than American brands—worth the splurge if you're making this often. If you're short on time, you can steam the potatoes in the microwave (pierce them first) for about 12-15 minutes instead of using a steamer basket.

Store the red bean paste in an airtight container in the fridge for up to 2 weeks, though it's best used within 5 days for peak freshness. The cinnamon and sesame seeds keep indefinitely in a cool, dark place—spice jars work perfectly. Leftover sweet potatoes reheat beautifully: wrap them in foil and warm in a 350°F oven for 10 minutes. For a make-ahead option, assemble the sweet potatoes and bean paste up to 1 day in advance, then dust with cinnamon just before serving. The flavors meld beautifully overnight, intensifying that wagashi essence.

Step-by-step instructions for Ben Yagi's smoky cinnamon sweet potatoes

Transform simple sweet potatoes into a smoky, cinnamon-kissed dessert with perfect charred edges.

Preheat your oven to 375°F and line a baking sheet with parchment paper. Pierce each of the 4 medium sweet potatoes with a fork in several places—this prevents them from bursting during cooking. Place the sweet potatoes in a steamer basket over the 4 cups of boiling water and steam for 15-20 minutes until they yield slightly to pressure when squeezed.

Here's the thing—steaming keeps the sweet potatoes moist while allowing them to develop that subtle smoky flavor later. If you don't have a steamer, you can wrap them in foil and bake at 375°F for 45-50 minutes instead. The key is achieving tender flesh that will absorb the anko mixture beautifully without falling apart.

Transfer the steamed sweet potatoes directly from the steamer to the preheated baking sheet. Using a sharp chef's knife, cut each potato lengthwise into 4 equal wedges, keeping the skin intact. Arrange the wedges cut-side up on the baking sheet.

Broil on high for 3-5 minutes until the edges develop deep char marks and the flesh becomes slightly caramelized. Watch closely—you want visible char but not burnt spots. The char adds smoky depth that balances the sweetness of the anko. Rotate the pan halfway through if needed for even browning.

In a medium bowl, combine the 1.5 cups of red bean paste (anko) with the 0.25 cup granulated sugar, 2 tablespoons ground cinnamon, 1 teaspoon vanilla extract, and 0.5 teaspoon sea salt. Mix thoroughly until the sugar and cinnamon are evenly distributed throughout the anko. The mixture should look thick and paste-like with visible cinnamon flecks.

This is where the magic happens—the cinnamon and sugar will caramelize slightly when heated, creating a fragrant crust on the sweet potatoes. If the mixture seems too dry, add 1 teaspoon of the 4 cups of reserved steaming water to loosen it slightly. The anko should coat the back of a spoon but still hold its shape.

Using a spoon, spread approximately 2 tablespoons of the anko mixture onto each sweet potato wedge, covering the cut surface completely. The filling should adhere to the warm potatoes without sliding off. Transfer the baking sheet to the oven and bake at 350°F for 12-15 minutes until the top layer becomes golden brown and slightly caramelized.

During the final 2 minutes of baking, sprinkle the 1 tablespoon toasted sesame seeds evenly over the top of each potato. The sesame seeds will toast further and add a nutty contrast to the sweet filling. The potatoes are done when they're heated through and the top layer has developed a glossy sheen from the caramelized sugar.

Remove the baking sheet from the oven and let the sweet potatoes cool for 5 minutes to allow the filling to set slightly. Drizzle each serving with 1 teaspoon of honey, letting it pool slightly in the center. The honey adds a final layer of sweetness that complements the smoky char and spiced anko.

Serve immediately while warm. The contrast between the crispy charred edges, creamy anko filling, and glossy honey drizzle creates a perfect balance of textures and flavors. Each bite should deliver warm, spiced sweet potato with a satisfying crunch from the charred exterior and sesame seeds.

Regional styles of this dish

Kyoto's Classic Anko Style

In Kyoto, this dessert takes on an especially refined form where the sweet potatoes are often steamed longer—up to 25 minutes—until they're almost falling apart. The local wagashi chefs there use Koyoan brand anko, which has a smoother texture and deeper sweetness.

I've noticed that Kyoto versions often include a touch of matcha powder (about ½ teaspoon) mixed into the anko filling for an earthy contrast.

The presentation is also more delicate, with the sweet potatoes arranged on a ceramic wagashi plate and garnished with edible gold leaf for special occasions. 🌸

Osaka's Bold Spice Twist

Osaka cooks bring their signature bold flavors to this dish by adding 1 teaspoon of shichimi togarashi (Japanese seven-spice chili) to the anko mixture. This creates a subtle heat that cuts through the sweetness beautifully.

The sweet potatoes here are often cut into thicker ½-inch slices rather than wedges, allowing for a more dramatic char when broiled. I've found that Osaka chefs also prefer to finish their version with a drizzle of yuzu kosho (citrus chili paste) instead of honey for a tangy kick.

The contrast between the smoky char and the citrusy finish is truly remarkable. 🌶️

Hokkaido's Winter Variation

Up in Hokkaido, where winters are long and cold, this dessert takes on a heartier form. The sweet potatoes are often replaced with purple sweet potatoes, which have a nuttier flavor and deeper color.

The anko filling gets a boost of 1 tablespoon of black sugar instead of regular granulated sugar, adding a molasses-like depth. Hokkaido cooks also incorporate toasted buckwheat flour (about 1 tablespoon) into the anko for a nutty crunch.