1. Preheat the oven to 400 degrees F. Place the butternut squash and apple chunks on a large baking sheet. Add olive oil, maple syrup, salt and pepper and toss. Roast the squash and apples for 25-30 minutes, turning once, until tender. Remove from the oven and cool to room temperature.
2. While the squash and apples are roasting, make the maple mustard dressing, if using. Combine garlic, mustards, syrup, vinegar, salt and pepper in a blender or food processor. Blend until smooth. With the machine running, pour in oil in a slow steady stream to emulsify. You should have about 2 cups of dressing. You will not need it all for the salad. You can store the leftover dressing in the refrigerator for about two weeks.
3. Place the mixed greens in a large salad bowl and add the butternut squash, apples, dried cranberries, pepitas, and feta cheese. Drizzle dressing over the salad to moisten and toss well. Serve immediately.
Note-you can also serve this salad with a store bought balsamic or cranberry dressing.