Place a rack in the center of your oven and preheat to 375°F. The oven needs to be hot to ensure even cooking and the right texture.
Arrange the sweet potatoes in a 9×13-inch baking dish without greasing it. Layer them evenly to ensure they cook uniformly.
In a small saucepan over medium heat, melt the butter. As it melts, it will start to bubble, releasing a nutty aroma.
Add the maple syrup, salt, cinnamon, ginger, and nutmeg to the melted butter. Stir well and bring to a gentle simmer for about 5 minutes. This allows the flavors to meld together beautifully.
Pour the butter mixture over the sweet potatoes in the baking dish and stir to coat them thoroughly. Make sure every slice is covered with that luscious sauce.
Cover the dish with aluminum foil. This will trap steam and help cook the sweet potatoes evenly, making them tender.
Bake the Candied Sweet Potatoes for 40 minutes. Stir them at the 20-minute mark to ensure they cook evenly.
After 40 minutes, remove the foil and stir once more. Continue baking for an additional 20 minutes. At this point, you should notice the sweet potatoes turning beautifully glazed and fork-tender.
Remove from the oven and sprinkle with fresh rosemary or thyme. Let them cool for 10 minutes before serving. This cooling period allows the sauce to thicken up a bit.