Step 1

Preheat oven to 400 degrees F. Coat a 9-by-13-inch baking dish with cooking spray.

Step 2

Place sweet potatoes in a single layer in the prepared pan. Mix water, brown sugar, soy sauce, mirin (or sherry), sesame oil and garlic in a small bowl. Pour over the sweet potatoes. Cover tightly with foil and bake until nearly tender, 35 to 45 minutes.

Step 3

Meanwhile, toast sesame seeds in a small dry skillet over low heat, stirring constantly, until light golden and fragrant, 2 to 3 minutes. Transfer to a plate to cool.

Step 4

Remove foil and baste the sweet potatoes with the sauce. Continue baking, uncovered, until fully tender, 10 to 15 minutes longer. Spoon glaze over the sweet potatoes, sprinkle with sesame seeds and serve.