Preheat the oven to 400°F.

Line a large baking sheet with parchment paper. Set aside.

Cut the butternut squash into 3/4-inch cubes and transfer to a large mixing bowl.

Drizzle squash with the melted butter. Sprinkle with the brown sugar, pumpkin pie spice, salt, and black pepper. Use a rubber spatula to toss squash until evenly coated in sugar mixture. Transfer to the prepared baking sheet.

Roast the squash on middle rack of oven, stirring halfway through cook time, until fork-tender and caramelized, 30-35 minutes.

Check to see that squash is done. Remove from oven or add time as needed.

Serve immediately.