Preheat the oven to 400°F (200°C). Toss the cubed butternut squash with olive oil, cinnamon, thyme, salt, and pepper. Spread evenly on a baking sheet and roast until tender and caramelized, about 25-30 minutes.
Remove the squash from the oven and let it cool slightly. Transfer to a mixing bowl and gently mash with a fork or potato masher until smooth but still a bit chunky.
In a small bowl, combine the breadcrumbs, melted butter, and a drizzle of maple syrup. Stir until the mixture is crumbly and fragrant.
Spread the mashed butternut squash evenly in a greased baking dish, smoothing the top with a spatula. Sprinkle the breadcrumb mixture evenly over the surface.
Bake the casserole in the preheated oven until the topping is golden brown and crispy, about 15-20 minutes.
Remove from the oven and let it rest for a few minutes. Drizzle with a little extra maple syrup if desired before serving to enhance the sweetness and presentation.