Toss butternut squash with olive oil and a little salt & pepper. Place on cookie sheet and roast until squash is tender (about 15-20 minutes).
Meanwhile, cut beets in half if small or wedges if larger. Place on small baking sheet and place in oven with the squash the last 5 minutes of cooking to heat them up.
On serving platter, arrange a bed of spinach. Top with the warm butternut squash and beets, feta cheese and nuts.
Drizzle balsamic glaze over top to taste (or lightly toss the spinach with vinaigrette first, if desired)