- Preheat oven to 220°C (425°F).
- In a large bowl, whisk together maple syrup, oil, garlic, lemon juice, mustard, salt, and pepper. Pour 60 mL (¼ cup) of maple sauce into a small bowl and set aside.
- Line a large baking sheet with parchment paper or aluminium foil. Place Brussel sprouts and onion in large bowl containing maple sauce and stir gently to coat. Transfer vegetables to baking sheet and bake on middle rack, until tender and golden brown, about 20 minutes, turning halfway through cooking.
- Remove baking sheet from oven and preheat broiler. Sprinkle vegetables with raisins, place salmon on top, and brush with maple sauce from small bowl. Return baking sheet to oven and grill salmon until it is lightly browned and flakes easily with a fork (about 7 minutes). Sprinkle with parsley before serving.
Give your vegetables ample space on the baking sheet to ensure they roast properly rather than steam.