Preheat oven to 400°F. Toss cubed butternut squash with olive oil, salt, and pepper. Spread on a baking sheet and roast for 30 minutes, or until tender and lightly browned.
In a small bowl, whisk together balsamic vinegar, Dijon mustard, and honey. Gradually whisk in extra virgin olive oil until emulsified. Season the dressing with salt and pepper.
In a large bowl, combine mixed greens, roasted butternut squash, dried cranberries, toasted walnuts, and feta cheese. Drizzle with the dressing and toss to combine.