Prepare the Brussels Sprouts: Preheat the oven to 425°F (220°C). Trim the tough ends from the Brussels sprouts and remove any loose or damaged outer leaves. Cut each sprout in half lengthwise, keeping smaller ones whole if needed.
Season the Sprouts: Place the Brussels sprouts in a large mixing bowl. Add the olive oil, salt, black pepper, and garlic powder. Toss until the cut surfaces are evenly coated.
Arrange for Roasting: Line a large baking sheet with parchment paper. Spread the Brussels sprouts in a single layer with the cut sides facing down where possible. Leave enough space between them for proper browning.
Roast Until Golden: Roast for 20–25 minutes, turning once halfway through if needed. The sprouts should be fork-tender with crisp, browned edges and lightly caramelized cut sides.
Prepare the Balsamic Glaze: While the Brussels sprouts roast, whisk together the balsamic vinegar, maple syrup, and Dijon mustard in a small bowl until smooth.
Add the Cranberries: Remove the baking sheet from the oven and scatter the dried cranberries over the hot Brussels sprouts. Drizzle the balsamic mixture over everything and toss gently to coat.
Finish with Pecans: Return the baking sheet to the oven for another 3–5 minutes, just until the glaze lightly coats the sprouts and the cranberries soften slightly. Remove from the oven and sprinkle with toasted pecans.
Garnish and Serve: Transfer the Brussels sprouts to a serving dish. Add chopped fresh parsley if desired and serve warm, with any glaze from the baking sheet spooned over the top.