1-First, peel and slice 5 to 6 medium sweet potatoes (3 to 4 pounds) into 1/2-inch thick slices. Place the slices in a greased 3-quart baking dish, sprinkle with the 1/2 teaspoon salt, and toss to coat evenly.

2-Preheat the oven to 375 degrees Fahrenheit (191 degrees Celsius). For the sauce, cut the 1/2 cup unsalted butter (8 tablespoons or 113 grams) in half for easier melting, then melt it over medium heat along with the 1 tablespoon water, 1/4 cup pure maple syrup (60 milliliters), 1 cup packed light or dark brown sugar (200 grams), 3/4 teaspoon ground cinnamon, 1/2 teaspoon ground nutmeg, and 1/2 teaspoon ground ginger.

3-Bring the mixture to a gentle boil and cook for 2 minutes without stirring. Remove from heat and stir in the 1 teaspoon pure vanilla extract and the optional 2 teaspoons orange zest.

4-Pour the sauce over the sweet potatoes in the dish and toss to combine. Bake in the preheated oven for 1 hour, stirring every 20 minutes; after the first 20 minutes, cover the dish with foil to ensure even cooking.

5-Once baked, sprinkle with the optional chopped fresh or dried rosemary for garnish, and let the dish cool uncovered for 10 minutes before serving.

6-Leftovers can be refrigerated for up to one week and reheated, as the sauce thickens upon cooling but thins when warmed. For variations, consider adding toasted pecans for extra texture, just like in the recipe tips.