Preheat oven to 400˚F. Lightly coat a baking sheet with nonstick spray and set aside.
Prepare the butternut squash by peeling it, removing the seeds, and chopping it into chunks. Arrange it in a single layer on the prepared baking sheet.
Drizzle the cubed squash with olive oil, maple syrup, brown sugar (optional), cinnamon, and nutmeg. Gently toss to combine.
Bake for 25 to 30 minutes, turning once mid-process. The squash should be fork-tender.
Garnish with fresh rosemary and serve.
Notes
Keep leftovers in an airtight container in the refrigerator for up to 4 days and in the freezer for up to 3 months.