Preheat Your Oven: Start by preheating your oven to 375°F (190°C). This ensures that your yams will cook evenly and caramelize beautifully.
Prepare the Yams: Peel the yams and slice them into 1/2-inch thick rounds. Place them in a large mixing bowl.
Make the Glaze: In a small saucepan over medium heat, melt the butter. Once melted, add the brown sugar, honey, rosemary, sea salt, cinnamon, nutmeg, and cayenne pepper (if using). Stir until the sugar dissolves and the mixture is well combined.
Coat the Yams: Pour the glaze over the sliced yams and toss them gently to ensure each piece is well-coated.
Arrange in Baking Dish: Transfer the glazed yams to a large baking dish, arranging them in a single layer for even cooking.
Bake: Cover the dish with foil and bake in the preheated oven for 30 minutes. Then, remove the foil and continue baking for another 15-20 minutes, or until the yams are tender and the glaze is thick and bubbly.
Garnish and Serve: Remove the yams from the oven and let them cool slightly. Before serving, sprinkle a pinch of sea salt over the top and garnish with additional rosemary if desired. Enjoy warm!