Preheat the oven to 375°F and line a baking sheet with parchment paper.
Spread the Brussels sprouts and onions on the baking sheet.
Pour the oil, tamari, and maple syrup over the veggies and mix well so they are coated.
Roast for 30 minutes, or until the onions are soft and the Brussels sprouts have browned, shrunk and crisped on the outside. Top with the fresh cilantro and/or parsley right before eating. You can also add hemp seeds if you like.