Preheat the oven. Set your oven to 400°F (200°C) and line a baking sheet with parchment paper for easy clean-up.
Prep the vegetables. Peel and cube the butternut squash into 1-inch pieces. Trim the Brussels sprouts and slice them in half. If they are large, you may want to quarter them for more even cooking.
Season the veggies. In a large bowl, toss the butternut squash and Brussels sprouts with olive oil, salt, pepper, garlic powder, smoked paprika, and herbs if using. For a slightly sweet touch, drizzle with maple syrup.
Spread on a baking sheet. Make sure the vegetables are in a single layer on the sheet. Overcrowding the pan will steam the vegetables instead of roasting them, preventing that caramelized exterior.
Roast. Place the veggies in the oven and roast for 25–30 minutes, stirring halfway through to ensure even browning. You’ll know they’re done when the edges of the Brussels sprouts are crispy, and the squash is tender and slightly caramelized.
Add finishing touches. Once the vegetables are out of the oven, feel free to sprinkle on some dried cranberries and chopped pecans for extra texture and flavor.