Preheat the Oven: Adjust the oven rack to the center position and preheat the oven to a high temperature of 400°F (200°C). Line a large, heavy-duty baking sheet with parchment paper.

Season the Vegetables: Place the cubed sweet potatoes and trimmed/halved Brussels sprouts into a large mixing bowl. Uniformity in size (1-inch cubes) is critical for even roasting.

Oil and Spice: Drizzle the 3 tablespoons of olive oil over the vegetables. Add 1 teaspoon of the kosher salt, the black pepper, and the optional garlic powder. Toss vigorously using your hands or a spatula until every piece is lightly coated.

First Roast Interval: Transfer the seasoned vegetables to the prepared baking sheet. It is crucial to spread them out in a true single layer without overcrowding (use two sheets if necessary). Roast for 15 minutes without stirring.

Mid-Way Stir: After 15 minutes, carefully remove the sheet from the oven. Use a metal spatula to scrape the vegetables off the pan and thoroughly toss or flip them. Return the sheet to the oven and roast for an additional 10 to 12 minutes.

Apply Optional Glaze (If Desired): Check for tenderness (sweet potatoes should be fork-tender and sprouts should have crispy edges). If glazing, remove the pan, drizzle the maple syrup and balsamic vinegar evenly over the hot vegetables, and toss quickly to coat. Return to the oven for a final 3 to 5 minutes to caramelize the glaze.

Serve: Remove the finished roasted vegetables from the oven. Taste and sprinkle the remaining ½ teaspoon of kosher salt over the mixture, if needed. Serve immediately while the exterior of the sprouts is still crispy.