Step 1

Preheat oven to 350°F. Layer sweet potato slices in a lightly greased 13- x 9-inch baking dish.

Step 2

Melt butter in a small saucepan over medium. Add sugars, stirring until well combined. Stir in cream; cook, stirring often, just until mixture comes to a simmer, 5 to 7 minutes. Remove from heat; stir in vanilla extract, cinnamon, salt, and nutmeg.

Step 3

Pour sugar mixture evenly over sweet potatoes, and cover with lightly greased aluminum foil.

Step 4

Bake, covered, in preheated oven, about 40 minutes. Uncover and gently stir potato mixture. Bake, uncovered, until potatoes are tender, 25 to 30 more minutes. Transfer potatoes to a serving bowl with a slotted spoon; pour syrup over potatoes. Serve immediately.