Roasted Sweet Potatoes with White Soy Sauce Recipe

Sweet potatoes are the kind of low-effort side that can taste more glamorous with the help of a few ingredients. This recipe starts with four halved sweet potatoes tossed with a simple seasoning mix of olive oil, salt, black pepper, and smoked paprika for a touch of woody smokiness. The seasoning permeates the skin, and the olive oil helps the skin crisp in the oven. 

The sweet potato halves are baked at 400°F until the skin turns crisp and the interiors turn creamy and lightly fluffy. The traditional finishing pat of butter that melts into the flesh is amped up with white soy sauce, or shiro shoyu, a type of Japanese soy sauce with a gentle sweetness; lighter umami; and a pale, light-amber color. The white soy sauce seasons the potatoes without muddying their orange color and adds complementary sweet-savory notes. A garnish of sliced scallions adds freshness with a mild onion flavor that ties everything together.

While this recipe is simple and straightforward, there are a few key techniques that ensure success. At the grocery store, choose sweet potatoes of similar size so they roast evenly. When baking, spread them in a single layer with cut sides down so the flesh makes direct contact with the pan and allows the natural sugars to caramelize. Also, don’t skip the mid-roast flip to promote even browning and super tender flesh. And, for white soy sauce, check your local Asian grocery store or source it online. If you can’t find it, regular soy sauce works; just use a lighter hand to avoid overpowering the potatoes or darkening their color.

White soy sauce vs. regular Japanese soy sauce: what’s the difference?

White soy sauce (shiro shoyu) is a Japanese soy sauce made with a much higher proportion of wheat (about 80% to 90% wheat to 10% to 20% soybeans). This gives it a pale amber color, a lighter body, and a gently sweet, subtly salty flavor. Regular dark Japanese soy sauce (koikuchi shoyu) is made with roughly equal parts soybeans and wheat, resulting in its deep color and strong umami. Use white soy sauce when you want seasoning without darkening a dish, such as clear broths, chawanmushi, and delicate sauces.

The best sweet potato variety for this recipe 

Unless otherwise specified in the recipe, a Beauregard sweet potato is one of the most common orange-fleshed sweet potatoes sold in U.S. supermarkets (though varieties like Covington are also widely sold.) Beauregards range from a light rose to coppery-red skin with orange flesh. Many cooks describe the flavor as sweet with mild nutty notes. Texture wise, the flesh cooks up creamy which makes this variety suitable for roasted sweet potatoes or sweet potato pie. 

Notes from the Food & Wine Test Kitchen

• Flipping the sweet potatoes halfway ensures even caramelization and avoids soggy skins.
• Partially cook the sweet potatoes in the microwave for about 3 to 4 minutes on HIGH before roasting to cut oven time in half.
• Top with toasted sesame seeds or chopped scallions for extra texture and flavor.

This recipe was developed by Tyson Cole; the text was written by Andee Gosnell.