Preheat the oven to 375 degrees Fahrenheit and spray a 13 x 9 x 2-inch baking dish with non-stick cooking spray.: Warm, even heat is the backbone of this recipe. As the oven approaches temperature you should feel a steady warmth from the vent and notice a faint dry scent of heated air. This step ensures the pan is ready to receive the glazed yams so they begin baking immediately, which promotes an even texture. If you skip preheating, the baking time will extend and the glaze may cook inconsistently. A frequent error is setting the oven temperature incorrectly, so double check that it reads 375 degrees Fahrenheit before you start.
Peel and cut 5-6 medium red garnet yams or sweet potatoes, into 1/2-inch thick slices or 2-inch bite-size pieces.: Cutting the yams uniformly is a sensory exercise, where you’ll notice their firm resistance and bright orange color. Even slices cook at the same rate and allow the glaze to coat each surface. If pieces are uneven, some will become mushy while others remain underdone. Avoid slicing too thin, which can lead to disintegration in the oven; aim for consistent thickness so each bite yields a tender yet intact texture.
Add 1/2 cup butter, 1/2 teaspoon kosher salt, 1 cup dark brown sugar, 1/4 cup granulated sugar, 1 teaspoon cornstarch, 2 teaspoons cinnamon, 1/4 teaspoon nutmeg, and 1/8 teaspoon cloves to a large pot.: Combining these elements in a pot creates the aromatic foundation of the glaze. As the sugars meet the butter you’ll begin to sense molasses and spice mingling, which signals that flavor is building. The cornstarch will play an invisible but crucial role by thickening the mixture as it heats. A common pitfall is adding the cornstarch dry, which can create lumps, so ensure it is evenly mixed into the other ingredients before heating.
Heat the mixture over medium-high heat. Whisk until the mixture is melted and combined.: As the mixture warms you’ll hear a gentle bubbling and smell a rich, caramel aroma. Whisking is tactile and rhythmic, breaking up any sugar clumps while encouraging a smooth emulsion between the butter and sugars. This process also activates the cornstarch , thickening the glaze into a glossy syrup. If the heat is too high, the sugars can scorch and give a bitter note, so maintain a steady medium-high flame and keep whisking until fully integrated.
Add the yam slices to the pot of glaze. Gently stir to coat the yams with the brown sugar glaze. Pour the coated yams into the prepared pan.: When you fold the yams into the warm glaze, each piece should pick up a shiny coat that clings and drips slowly. The sound is soft, a muted stir, and visually you’ll see the slices become lacquered. Pouring them into the dish, arrange them so they sit comfortably without severe overcrowding, which helps heat circulate during baking. A common mistake is over-stirring, which can break delicate pieces; be gentle to preserve shape.
Cover the baking dish with aluminum foil and bake for 40 minutes. Open the oven to stir and coat the yams with the glaze. Replace the foil and finish baking the yams for an additional 15 minutes.: The foil traps steam, gently cooking the yams through while the glaze seeps into their flesh. After the initial 40 minutes you should detect a deepened sugar scent and see bubbling edges beneath the foil. Stirring at this point refreshes the glaze on each piece and promotes even caramelization. Replace the foil so the tops do not brown too quickly. Overbaking at this stage can dry the edges and harden the glaze, so adhere to the times and check for fork tenderness.
Remove the yams from the oven when they are fork-tender and enjoy!: A fork should glide into the yams with minimal resistance and the glaze will be glossy and slightly syrupy around the pieces. The aroma should be warm cinnamon and caramel, and the surface will shimmer. Allow the dish to rest briefly so the glaze settles; serving immediately can cause the syrup to run too freely. One common misstep is pulling them out too soon before they’re fully tender, resulting in a firmer texture than intended. Let them rest for a few minutes to achieve the ideal balance of soft interior and sticky coating.