Meanwhile, toss Brussels sprouts with 2 Tbsp. olive oil, sea salt and pepper. Place on a rimmed baking sheet and roast for 35-40 minutes or until tender and golden brown; shake the pan every 10 minutes to ensure even cooking. Remove from oven; set aside.
In a large bowl, combine cooked quinoa, Brussels sprouts, spinach, cilantro and cashews.
In a small bowl, whisk vinegar, remaining 1 Tbsp. olive oil, maple syrup or honey, sea salt and pepper; pour over quinoa mixture and toss to combine. Serve.