Preheat the oven to 400 F. Place the squash on a rimmed baking sheet, drizzle over the melted butter, and sprinkle over the brown sugar and sage leaves. Season with salt and pepper, and toss to combine. Spread out in a single layer on the baking sheet, allowing space in between the cubes when possible and making sure the sage leaves are somewhat evenly distributed.
Roast for about 25 minutes until tender and lightly browned on the bottom. Drizzle over the maple syrup, use a spatula to toss the squash with the syrup, and spread it back out on the baking sheet. Roast for another 10 or so minutes, until it is caramelized in spots and very tender. Serve hot or warm.
Notes
You can buy pre-cut butternut squash for this recipe. Otherwise, peel and cut a full squash; this tends to be fresher.