Preheat oven to 375°. Grease an 8x8 inch baking dish.
Peel squash with a vegetable peeler; halve lengthwise, scoop out seeds and cut into 1-inch pieces. Place squash cubes into prepared baking dish and drizzle with melted butter.
Combine brown sugar, cinnamon, salt and pepper in a small bowl and stir to mix. Sprinkle mixture over squash and stir to coat squash evenly. Bake, stirring twice, until squash is tender and sauce is bubbly, 45-50 minutes. Serve hot.