Place the diced butternut squash on a baking sheet, drizzle with olive oil, and season with salt and pepper. Roast for 25-30 minutes, until tender.
While the squash is roasting, rinse the quinoa under cold water. In a saucepan, bring the water to a boil, add the quinoa, reduce heat, and simmer for 15 minutes or until water is absorbed.
In a large mixing bowl, combine the cooked quinoa, roasted butternut squash, and fresh baby spinach. Toss gently to mix.