01 -
Arrange a rack in the center of the oven and heat to 350°F. Grease a 9x13-inch baking dish with the softened butter.
02 -
Peel the sweet potatoes and slice them into 1/2-inch rounds. Arrange them in the baking dish in slightly overlapping rows.
03 -
Melt the butter in a small saucepan over medium heat. Stir in the brown sugar, granulated sugar, orange juice, cinnamon, nutmeg, and salt until the sugar is mostly dissolved and the mixture looks smooth. Remove from the heat and stir in the vanilla.
04 -
Pour the hot syrup evenly over the sweet potatoes. Cover the dish tightly with foil and bake for 35 minutes.
05 -
Remove the foil and carefully spoon the syrup over the top slices. Bake uncovered for 20-25 minutes more, basting once, until the sweet potatoes are fork-tender and glossy.
06 -
Let the candied yams rest for 10 minutes before serving. Spoon the thickened syrup from the bottom of the dish over each portion.