Preheat your oven to 375°F. Butter a 9 x 13-inch baking dish and set it aside.
Wash, peel, and slice the sweet potatoes into ½-inch thick rounds. Place the sweet potatoes in the buttered baking dish and set them aside.
Heat the butter, granulated sugar, brown sugar, cinnamon, ginger, nutmeg, cloves, and salt in a medium saucepan over medium-high heat until the butter melts. Stir in the vanilla extract and remove the pan from the heat.
Pour the butter and sugar mixture over the sweet potatoes and use a wooden spoon or your hands to stir the sweet potatoes and make sure each potato slice is coated in the syrup. Cover the pan with foil and bake the yams in the preheated oven for 30 minutes.
After 30 minutes, remove the foil from the pan, carefully spoon some of the cooking syrup over the yams, and continue cooking the yams, uncovered, for an additional 20 to 25 minutes, or until the sweet potatoes can be easily pierced with a fork and the cooking liquid is syrupy.
Allow the candied yams to cool for about 10 minutes and enjoy!