Prepare the Oven and Baking Surface: Preheat your oven to 425°F (220°C). Line a large baking tray with parchment paper or aluminum foil to prevent sticking, then lightly spray the surface with a nonstick cooking spray to ensure easy cleanup and flawless roasting.
Coat the Sweet Potatoes: Place the diced sweet potatoes on the prepared baking tray. Drizzle with olive oil and sprinkle the kosher salt over them. Toss gently using your hands or a spatula until each cube is thoroughly coated in oil and seasoning. Arrange the sweet potatoes in a single, even layer without overlapping, which helps them roast evenly and develop a nice crisp.
Initial Roasting Phase: Slide the tray into the preheated oven and roast for about 20 minutes. This first phase allows the sweet potatoes to soften on the inside while starting to caramelize on the edges.
Prepare the Maple-Cinnamon Glaze: While the potatoes roast, whisk together the pure maple syrup and ground cinnamon in a small bowl until fully combined. This sweet and fragrant glaze will add a delightful finish.
Glaze and Finish Roasting: Remove the baking tray from the oven carefully. Drizzle the maple-cinnamon mixture evenly over the sweet potatoes. Using a spatula, toss the cubes gently to coat them with the glaze and redistribute them evenly across the tray. Return the tray to the oven and continue roasting for another 5 to 10 minutes, depending on your preferred crispiness. Stir halfway through to ensure all sides are nicely roasted.
Serve and Garnish: Once golden and tender, take the sweet potatoes out of the oven. Transfer them to a serving dish and, if desired, sprinkle chopped candied pecans or walnuts on top for a crunchy, sweet contrast. Serve immediately and enjoy!