Preheat your oven to 425°F (220°C) with the rack in the upper-middle position. On a large rimmed baking sheet, toss the halved Brussels sprouts and 1/2-inch cubed butternut squash with olive oil, salt, and black pepper. Arrange the Brussels sprouts cut-side down and roast for 8 minutes to get a head start.

While the veggies pre-roast, whisk together the pure maple syrup, Dijon mustard, whole-grain mustard, apple cider vinegar, grated garlic, and fresh rosemary in a small bowl.

Remove the sheet pan from the oven, push the veggies to the outer edges, and place the 4 salmon fillets skin-side down in the center. Brush two-thirds of the maple Dijon glaze generously over the salmon and drizzle the remaining glaze over the Brussels sprouts and squash.

Return to the 425°F oven for 9–11 minutes until the salmon flakes easily with a fork (125°F–130°F internal temperature) and the edges of the Brussels sprouts are crispy and caramelized. Scatter toasted pecans and dried cranberries over the pan before serving.