First, it's time to roast that butternut! I always roast my butternut with coconut oil, but choose whatever fat you like that is safe for high heat.
Preheat your oven to 425 degrees. Melt your fat and toss it with the butternut squash cubes. Add the 1/2 tsp salt and toss again. Arrange cubes in a single layer on a parchment lined baking sheet (for maximum sweetness and crispness, do the parchment!) Roast in the preheated oven for about 30 minutes, flipping/stirring once in the middle of cook time, or until browned, soft inside and crisp outside.
Set your butternut aside to cool while you prepare the rest of the salad. Combine your baby spinach, chopped apple, and walnuts in a med-large salad bowl and set aside. In a small bowl, whisk together the olive oil, lemon, lime and orange juice, and maple syrup if you are adding that. (The salad maple syrup will really sweeten up the dressing, so only add this if you want a pretty sweet salad!)
Now add the cooled butternut squash to the salad bowl. Just before serving, whisk up the dressing again, drizzle over the salad a little at a time, and toss. Serve alone or as a delicious side dish!