Preheat the oven to 400°F (200°C).
Prepare the butternut squash by peeling and dicing it into uniform pieces.
Toss the squash with olive oil, salt, and pepper, then spread it on a baking sheet.
Roast the squash for 25-30 minutes or until golden brown and tender, turning halfway through.
While the squash is roasting, cook the quinoa according to package instructions.
In a large bowl, combine the fresh spinach, roasted squash, cooked quinoa, red onion, walnuts, cranberries, and feta cheese.
In a small bowl, whisk together olive oil, balsamic vinegar, and a pinch of salt and pepper to create the dressing.
Drizzle the dressing over the salad and toss gently until everything is coated evenly.
Taste and adjust seasoning if necessary before serving warm or at room temperature.